text: # -*- coding: utf-8 -*-
  #
  # vim: sw=4:expandtab:foldmethod=marker
  #
  # Copyright (c) 2006, Mathieu Fenniak
  # Copyright (c) 2007, Ashish Kulkarni <kulkarni.ashish@gmail.com>
  #
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met:
  #
  # * Redistributions of source code must retain the above copyright notice,
  # this list of conditions and the following disclaimer.
  # * Redistributions in binary form must reproduce the above copyright notice,
  # this list of conditions and the following disclaimer in the documentation
  # and/or other materials provided with the distribution.
  # * The name of the author may not be used to endorse or promote products
  # derived from this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  # POSSIBILITY OF SUCH DAMAGE.
  
  """
  A pure-Python PDF library with an increasing number of capabilities.
  See README for links to FAQ, documentation, homepage, etc.
  """
  
  __author__ = "Mathieu Fenniak"
  __author_email__ = "biziqe@mathieu.fenniak.net"
  
  __maintainer__ = "Phaseit, Inc."
  __maintainer_email = "PyPDF2@phaseit.net"
  
  import string
  import math
  import struct
  import sys
  import uuid
  from sys import version_info
  if version_info < ( 3, 0 ):
      from cStringIO import StringIO
  else:
      from io import StringIO
  
  if version_info < ( 3, 0 ):
      BytesIO = StringIO
  else:
      from io import BytesIO
  
  from . import filters
  from . import utils
  import warnings
  import codecs
  from .generic import *
  from .utils import readNonWhitespace, readUntilWhitespace, ConvertFunctionsToVirtualList
  from .utils import isString, b_, u_, ord_, chr_, str_, formatWarning
  
  if version_info < ( 2, 4 ):
     from sets import ImmutableSet as frozenset
  
  if version_info < ( 2, 5 ):
      from md5 import md5
  else:
      from hashlib import md5
  import uuid
  
  
  class PdfFileWriter(object):
      """
      This class supports writing PDF files out, given pages produced by another
      class (typically :class:`PdfFileReader<PdfFileReader>`).
      """
      def __init__(self):
          self._header = b_("%PDF-1.3")
          self._objects = []  # array of indirect objects
  
          # The root of our page tree node.
          pages = DictionaryObject()
          pages.update({
                  NameObject("/Type"): NameObject("/Pages"),
                  NameObject("/Count"): NumberObject(0),
                  NameObject("/Kids"): ArrayObject(),
                  })
          self._pages = self._addObject(pages)
  
          # info object
          info = DictionaryObject()
          info.update({
                  NameObject("/Producer"): createStringObject(codecs.BOM_UTF16_BE + u_("PyPDF2").encode('utf-16be'))
                  })
          self._info = self._addObject(info)
  
          # root object
          root = DictionaryObject()
          root.update({
              NameObject("/Type"): NameObject("/Catalog"),
              NameObject("/Pages"): self._pages,
              })
          self._root = None
          self._root_object = root
  
      def _addObject(self, obj):
          self._objects.append(obj)
          return IndirectObject(len(self._objects), 0, self)
  
      def getObject(self, ido):
          if ido.pdf != self:
              raise ValueError("pdf must be self")
          return self._objects[ido.idnum - 1]
  
      def _addPage(self, page, action):
          assert page["/Type"] == "/Page"
          page[NameObject("/Parent")] = self._pages
          page = self._addObject(page)
          pages = self.getObject(self._pages)
          action(pages["/Kids"], page)
          pages[NameObject("/Count")] = NumberObject(pages["/Count"] + 1)
  
      def addPage(self, page):
          """
          Adds a page to this PDF file.  The page is usually acquired from a
          :class:`PdfFileReader<PdfFileReader>` instance.
  
          :param PageObject page: The page to add to the document. Should be
              an instance of :class:`PageObject<PyPDF2.pdf.PageObject>`
          """
          self._addPage(page, list.append)
  
      def insertPage(self, page, index=0):
          """
          Insert a page in this PDF file. The page is usually acquired from a
          :class:`PdfFileReader<PdfFileReader>` instance.
  
          :param PageObject page: The page to add to the document.  This
              argument should be an instance of :class:`PageObject<pdf.PageObject>`.
          :param int index: Position at which the page will be inserted.
          """
          self._addPage(page, lambda l, p: l.insert(index, p))
  
      def getPage(self, pageNumber):
          """
          Retrieves a page by number from this PDF file.
  
          :param int pageNumber: The page number to retrieve
              (pages begin at zero)
          :return: the page at the index given by *pageNumber*
          :rtype: :class:`PageObject<pdf.PageObject>`
          """
          pages = self.getObject(self._pages)
          # XXX: crude hack
          return pages["/Kids"][pageNumber].getObject()
  
      def getNumPages(self):
          """
          :return: the number of pages.
          :rtype: int
          """
          pages = self.getObject(self._pages)
          return int(pages[NameObject("/Count")])
  
      def addBlankPage(self, width=None, height=None):
          """
          Appends a blank page to this PDF file and returns it. If no page size
          is specified, use the size of the last page.
  
          :param float width: The width of the new page expressed in default user
              space units.
          :param float height: The height of the new page expressed in default
              user space units.
          :return: the newly appended page
          :rtype: :class:`PageObject<PyPDF2.pdf.PageObject>`
          :raises PageSizeNotDefinedError: if width and height are not defined
              and previous page does not exist.
          """
          page = PageObject.createBlankPage(self, width, height)
          self.addPage(page)
          return page
  
      def insertBlankPage(self, width=None, height=None, index=0):
          """
          Inserts a blank page to this PDF file and returns it. If no page size
          is specified, use the size of the last page.
  
          :param float width: The width of the new page expressed in default user
              space units.
          :param float height: The height of the new page expressed in default
              user space units.
          :param int index: Position to add the page.
          :return: the newly appended page
          :rtype: :class:`PageObject<PyPDF2.pdf.PageObject>`
          :raises PageSizeNotDefinedError: if width and height are not defined
              and previous page does not exist.
          """
          if width is None or height is None and \
                  (self.getNumPages() - 1) >= index:
              oldpage = self.getPage(index)
              width = oldpage.mediaBox.getWidth()
              height = oldpage.mediaBox.getHeight()
          page = PageObject.createBlankPage(self, width, height)
          self.insertPage(page, index)
          return page
  
      def addJS(self, javascript):
          """
          Add Javascript which will launch upon opening this PDF.
  
          :param str javascript: Your Javascript.
  
          >>> output.addJS("this.print({bUI:true,bSilent:false,bShrinkToFit:true});")
          # Example: This will launch the print window when the PDF is opened.
          """
          js = DictionaryObject()
          js.update({
                  NameObject("/Type"): NameObject("/Action"),
                  NameObject("/S"): NameObject("/JavaScript"),
                  NameObject("/JS"): NameObject("(%s)" % javascript)
                  })
          js_indirect_object = self._addObject(js)
  
          # We need a name for parameterized javascript in the pdf file, but it can be anything.
          js_string_name = str(uuid.uuid4())
  
          js_name_tree = DictionaryObject()
          js_name_tree.update({
                  NameObject("/JavaScript"): DictionaryObject({
                    NameObject("/Names"): ArrayObject([createStringObject(js_string_name), js_indirect_object])
                  })
                })
          self._addObject(js_name_tree)
  
          self._root_object.update({
                  NameObject("/OpenAction"): js_indirect_object,
                  NameObject("/Names"): js_name_tree
                  })
  
      def addAttachment(self, fname, fdata):
          """
          Embed a file inside the PDF.
  
          :param str fname: The filename to display.
          :param str fdata: The data in the file.
        
          Reference:
          https://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/PDF32000_2008.pdf
          Section 7.11.3
          """
          
          # We need 3 entries:
          # * The file's data
          # * The /Filespec entry
          # * The file's name, which goes in the Catalog
          
  
          # The entry for the file
          """ Sample:
          8 0 obj
          <<
           /Length 12
           /Type /EmbeddedFile
          >>
          stream
          Hello world!
          endstream
          endobj        
          """
          file_entry = DecodedStreamObject()
          file_entry.setData(fdata)
          file_entry.update({
                  NameObject("/Type"): NameObject("/EmbeddedFile")
                  })
  
          # The Filespec entry
          """ Sample:
          7 0 obj
          <<
           /Type /Filespec
           /F (hello.txt)
           /EF << /F 8 0 R >>
          >>
          """
          efEntry = DictionaryObject()
          efEntry.update({ NameObject("/F"):file_entry })
          
          filespec = DictionaryObject()
          filespec.update({
                  NameObject("/Type"): NameObject("/Filespec"),
                  NameObject("/F"): createStringObject(fname),  # Perhaps also try TextStringObject
                  NameObject("/EF"): efEntry
                  })
                  
          # Then create the entry for the root, as it needs a reference to the Filespec
          """ Sample:
          1 0 obj
          <<
           /Type /Catalog
           /Outlines 2 0 R
           /Pages 3 0 R
           /Names << /EmbeddedFiles << /Names [(hello.txt) 7 0 R] >> >>
          >>
          endobj
          
          """
          embeddedFilesNamesDictionary = DictionaryObject()
          embeddedFilesNamesDictionary.update({
                  NameObject("/Names"): ArrayObject([createStringObject(fname), filespec])
                  })
          
          embeddedFilesDictionary = DictionaryObject()
          embeddedFilesDictionary.update({
                  NameObject("/EmbeddedFiles"): embeddedFilesNamesDictionary
                  })
          # Update the root
          self._root_object.update({
                  NameObject("/Names"): embeddedFilesDictionary
                  })
  
      def appendPagesFromReader(self, reader, after_page_append=None):
          """
          Copy pages from reader to writer. Includes an optional callback parameter
          which is invoked after pages are appended to the writer.
          
          :param reader: a PdfFileReader object from which to copy page
              annotations to this writer object.  The writer's annots
          will then be updated
          :callback after_page_append (function): Callback function that is invoked after
              each page is appended to the writer. Callback signature:
  
              :param writer_pageref (PDF page reference): Reference to the page
                  appended to the writer.
          """
          # Get page count from writer and reader
          reader_num_pages = reader.getNumPages()
          writer_num_pages = self.getNumPages()
  
          # Copy pages from reader to writer
          for rpagenum in range(0, reader_num_pages):
              reader_page = reader.getPage(rpagenum)
              self.addPage(reader_page)
              writer_page = self.getPage(writer_num_pages+rpagenum)
              # Trigger callback, pass writer page as parameter
              if callable(after_page_append): after_page_append(writer_page)
  
      def updatePageFormFieldValues(self, page, fields):
          '''
          Update the form field values for a given page from a fields dictionary.
          Copy field texts and values from fields to page.
  
          :param page: Page reference from PDF writer where the annotations
              and field data will be updated.
          :param fields: a Python dictionary of field names (/T) and text
              values (/V)
          '''
          # Iterate through pages, update field values
          for j in range(0, len(page['/Annots'])):
              writer_annot = page['/Annots'][j].getObject()
              for field in fields:
                  if writer_annot.get('/T') == field:
                      writer_annot.update({
                          NameObject("/V"): TextStringObject(fields[field])
                      })
  
      def cloneReaderDocumentRoot(self, reader):
          '''
          Copy the reader document root to the writer.
          
          :param reader:  PdfFileReader from the document root should be copied.
          :callback after_page_append
          '''
          self._root_object = reader.trailer['/Root']
  
      def cloneDocumentFromReader(self, reader, after_page_append=None):
          '''
          Create a copy (clone) of a document from a PDF file reader
  
          :param reader: PDF file reader instance from which the clone
              should be created.
          :callback after_page_append (function): Callback function that is invoked after
              each page is appended to the writer. Signature includes a reference to the
              appended page (delegates to appendPagesFromReader). Callback signature:
  
              :param writer_pageref (PDF page reference): Reference to the page just
                  appended to the document.
          '''
          self.cloneReaderDocumentRoot(reader)
          self.appendPagesFromReader(reader, after_page_append)
  
      def encrypt(self, user_pwd, owner_pwd = None, use_128bit = True):
          """
          Encrypt this PDF file with the PDF Standard encryption handler.
  
          :param str user_pwd: The "user password", which allows for opening
              and reading the PDF file with the restrictions provided.
          :param str owner_pwd: The "owner password", which allows for
              opening the PDF files without any restrictions.  By default,
              the owner password is the same as the user password.
          :param bool use_128bit: flag as to whether to use 128bit
              encryption.  When false, 40bit encryption will be used.  By default,
              this flag is on.
          """
          import time, random
          if owner_pwd == None:
              owner_pwd = user_pwd
          if use_128bit:
              V = 2
              rev = 3
              keylen = int(128 / 8)
          else:
              V = 1
              rev = 2
              keylen = int(40 / 8)
          # permit everything:
          P = -1
          O = ByteStringObject(_alg33(owner_pwd, user_pwd, rev, keylen))
          ID_1 = ByteStringObject(md5(b_(repr(time.time()))).digest())
          ID_2 = ByteStringObject(md5(b_(repr(random.random()))).digest())
          self._ID = ArrayObject((ID_1, ID_2))
          if rev == 2:
              U, key = _alg34(user_pwd, O, P, ID_1)
          else:
              assert rev == 3
              U, key = _alg35(user_pwd, rev, keylen, O, P, ID_1, False)
          encrypt = DictionaryObject()
          encrypt[NameObject("/Filter")] = NameObject("/Standard")
          encrypt[NameObject("/V")] = NumberObject(V)
          if V == 2:
              encrypt[NameObject("/Length")] = NumberObject(keylen * 8)
          encrypt[NameObject("/R")] = NumberObject(rev)
          encrypt[NameObject("/O")] = ByteStringObject(O)
          encrypt[NameObject("/U")] = ByteStringObject(U)
          encrypt[NameObject("/P")] = NumberObject(P)
          self._encrypt = self._addObject(encrypt)
          self._encrypt_key = key
  
      def write(self, stream):
          """
          Writes the collection of pages added to this object out as a PDF file.
  
          :param stream: An object to write the file to.  The object must support
              the write method and the tell method, similar to a file object.
          """
          if hasattr(stream, 'mode') and 'b' not in stream.mode:
              warnings.warn("File <%s> to write to is not in binary mode. It may not be written to correctly." % stream.name)
          debug = False
          import struct
  
          if not self._root:
              self._root = self._addObject(self._root_object)
  
          externalReferenceMap = {}
  
          # PDF objects sometimes have circular references to their /Page objects
          # inside their object tree (for example, annotations).  Those will be
          # indirect references to objects that we've recreated in this PDF.  To
          # address this problem, PageObject's store their original object
          # reference number, and we add it to the external reference map before
          # we sweep for indirect references.  This forces self-page-referencing
          # trees to reference the correct new object location, rather than
          # copying in a new copy of the page object.
          for objIndex in range(len(self._objects)):
              obj = self._objects[objIndex]
              if isinstance(obj, PageObject) and obj.indirectRef != None:
                  data = obj.indirectRef
                  if data.pdf not in externalReferenceMap:
                      externalReferenceMap[data.pdf] = {}
                  if data.generation not in externalReferenceMap[data.pdf]:
                      externalReferenceMap[data.pdf][data.generation] = {}
                  externalReferenceMap[data.pdf][data.generation][data.idnum] = IndirectObject(objIndex + 1, 0, self)
  
          self.stack = []
          if debug: print(("ERM:", externalReferenceMap, "root:", self._root))
          self._sweepIndirectReferences(externalReferenceMap, self._root)
          del self.stack
  
          # Begin writing:
          object_positions = []
          stream.write(self._header + b_("\n"))
          for i in range(len(self._objects)):
              idnum = (i + 1)
              obj = self._objects[i]
              object_positions.append(stream.tell())
              stream.write(b_(str(idnum) + " 0 obj\n"))
              key = None
              if hasattr(self, "_encrypt") and idnum != self._encrypt.idnum:
                  pack1 = struct.pack("<i", i + 1)[:3]
                  pack2 = struct.pack("<i", 0)[:2]
                  key = self._encrypt_key + pack1 + pack2
                  assert len(key) == (len(self._encrypt_key) + 5)
                  md5_hash = md5(key).digest()
                  key = md5_hash[:min(16, len(self._encrypt_key) + 5)]
              obj.writeToStream(stream, key)
              stream.write(b_("\nendobj\n"))
  
          # xref table
          xref_location = stream.tell()
          stream.write(b_("xref\n"))
          stream.write(b_("0 %s\n" % (len(self._objects) + 1)))
          stream.write(b_("%010d %05d f \n" % (0, 65535)))
          for offset in object_positions:
              stream.write(b_("%010d %05d n \n" % (offset, 0)))
  
          # trailer
          stream.write(b_("trailer\n"))
          trailer = DictionaryObject()
          trailer.update({
                  NameObject("/Size"): NumberObject(len(self._objects) + 1),
                  NameObject("/Root"): self._root,
                  NameObject("/Info"): self._info,
                  })
          if hasattr(self, "_ID"):
              trailer[NameObject("/ID")] = self._ID
          if hasattr(self, "_encrypt"):
              trailer[NameObject("/Encrypt")] = self._encrypt
          trailer.writeToStream(stream, None)
  
          # eof
          stream.write(b_("\nstartxref\n%s\n%%%%EOF\n" % (xref_location)))
  
      def addMetadata(self, infos):
          """
          Add custom metadata to the output.
  
          :param dict infos: a Python dictionary where each key is a field
              and each value is your new metadata.
          """
          args = {}
          for key, value in list(infos.items()):
              args[NameObject(key)] = createStringObject(value)
          self.getObject(self._info).update(args)
  
      def _sweepIndirectReferences(self, externMap, data):
          debug = False
          if debug: print((data, "TYPE", data.__class__.__name__))
          if isinstance(data, DictionaryObject):
              for key, value in list(data.items()):
                  origvalue = value
                  value = self._sweepIndirectReferences(externMap, value)
                  if isinstance(value, StreamObject):
                      # a dictionary value is a stream.  streams must be indirect
                      # objects, so we need to change this value.
                      value = self._addObject(value)
                  data[key] = value
              return data
          elif isinstance(data, ArrayObject):
              for i in range(len(data)):
                  value = self._sweepIndirectReferences(externMap, data[i])
                  if isinstance(value, StreamObject):
                      # an array value is a stream.  streams must be indirect
                      # objects, so we need to change this value
                      value = self._addObject(value)
                  data[i] = value
              return data
          elif isinstance(data, IndirectObject):
              # internal indirect references are fine
              if data.pdf == self:
                  if data.idnum in self.stack:
                      return data
                  else:
                      self.stack.append(data.idnum)
                      realdata = self.getObject(data)
                      self._sweepIndirectReferences(externMap, realdata)
                      return data
              else:
                  newobj = externMap.get(data.pdf, {}).get(data.generation, {}).get(data.idnum, None)
                  if newobj == None:
                      try:
                          newobj = data.pdf.getObject(data)
                          self._objects.append(None) # placeholder
                          idnum = len(self._objects)
                          newobj_ido = IndirectObject(idnum, 0, self)
                          if data.pdf not in externMap:
                              externMap[data.pdf] = {}
                          if data.generation not in externMap[data.pdf]:
                              externMap[data.pdf][data.generation] = {}
                          externMap[data.pdf][data.generation][data.idnum] = newobj_ido
                          newobj = self._sweepIndirectReferences(externMap, newobj)
                          self._objects[idnum-1] = newobj
                          return newobj_ido
                      except ValueError:
                          # Unable to resolve the Object, returning NullObject instead.
                          return NullObject()
                  return newobj
          else:
              return data
  
      def getReference(self, obj):
          idnum = self._objects.index(obj) + 1
          ref = IndirectObject(idnum, 0, self)
          assert ref.getObject() == obj
          return ref
  
      def getOutlineRoot(self):
          if '/Outlines' in self._root_object:
              outline = self._root_object['/Outlines']
              idnum = self._objects.index(outline) + 1
              outlineRef = IndirectObject(idnum, 0, self)
              assert outlineRef.getObject() == outline
          else:
              outline = TreeObject()
              outline.update({ })
              outlineRef = self._addObject(outline)
              self._root_object[NameObject('/Outlines')] = outlineRef
  
          return outline
  
      def getNamedDestRoot(self):
          if '/Names' in self._root_object and isinstance(self._root_object['/Names'], DictionaryObject):
              names = self._root_object['/Names']
              idnum = self._objects.index(names) + 1
              namesRef = IndirectObject(idnum, 0, self)
              assert namesRef.getObject() == names
              if '/Dests' in names and isinstance(names['/Dests'], DictionaryObject):
                  dests = names['/Dests']
                  idnum = self._objects.index(dests) + 1
                  destsRef = IndirectObject(idnum, 0, self)
                  assert destsRef.getObject() == dests
                  if '/Names' in dests:
                      nd = dests['/Names']
                  else:
                      nd = ArrayObject()
                      dests[NameObject('/Names')] = nd
              else:
                  dests = DictionaryObject()
                  destsRef = self._addObject(dests)
                  names[NameObject('/Dests')] = destsRef
                  nd = ArrayObject()
                  dests[NameObject('/Names')] = nd
  
          else:
              names = DictionaryObject()
              namesRef = self._addObject(names)
              self._root_object[NameObject('/Names')] = namesRef
              dests = DictionaryObject()
              destsRef = self._addObject(dests)
              names[NameObject('/Dests')] = destsRef
              nd = ArrayObject()
              dests[NameObject('/Names')] = nd
  
          return nd
  
      def addBookmarkDestination(self, dest, parent=None):
          destRef = self._addObject(dest)
  
          outlineRef = self.getOutlineRoot()
  
          if parent == None:
              parent = outlineRef
  
          parent = parent.getObject()
          #print parent.__class__.__name__
          parent.addChild(destRef, self)
  
          return destRef
  
      def addBookmarkDict(self, bookmark, parent=None):
          bookmarkObj = TreeObject()
          for k, v in list(bookmark.items()):
              bookmarkObj[NameObject(str(k))] = v
          bookmarkObj.update(bookmark)
  
          if '/A' in bookmark:
              action = DictionaryObject()
              for k, v in list(bookmark['/A'].items()):
                  action[NameObject(str(k))] = v
              actionRef = self._addObject(action)
              bookmarkObj[NameObject('/A')] = actionRef
  
          bookmarkRef = self._addObject(bookmarkObj)
  
          outlineRef = self.getOutlineRoot()
  
          if parent == None:
              parent = outlineRef
  
          parent = parent.getObject()
          parent.addChild(bookmarkRef, self)
  
          return bookmarkRef
  
      def addBookmark(self, title, pagenum, parent=None, color=None, bold=False, italic=False, fit='/Fit', *args):
          """
          Add a bookmark to this PDF file.
  
          :param str title: Title to use for this bookmark.
          :param int pagenum: Page number this bookmark will point to.
          :param parent: A reference to a parent bookmark to create nested
              bookmarks.
          :param tuple color: Color of the bookmark as a red, green, blue tuple
              from 0.0 to 1.0
          :param bool bold: Bookmark is bold
          :param bool italic: Bookmark is italic
          :param str fit: The fit of the destination page. See
              :meth:`addLink()<addLink>` for details.
          """
          pageRef = self.getObject(self._pages)['/Kids'][pagenum]
          action = DictionaryObject()
          zoomArgs = []
          for a in args:
              if a is not None:
                  zoomArgs.append(NumberObject(a))
              else:
                  zoomArgs.append(NullObject())
          dest = Destination(NameObject("/"+title + " bookmark"), pageRef, NameObject(fit), *zoomArgs)
          destArray = dest.getDestArray()
          action.update({
              NameObject('/D') : destArray,
              NameObject('/S') : NameObject('/GoTo')
          })
          actionRef = self._addObject(action)
  
          outlineRef = self.getOutlineRoot()
  
          if parent == None:
              parent = outlineRef
  
          bookmark = TreeObject()
  
          bookmark.update({
              NameObject('/A'): actionRef,
              NameObject('/Title'): createStringObject(title),
          })
  
          if color is not None:
              bookmark.update({NameObject('/C'): ArrayObject([FloatObject(c) for c in color])})
  
          format = 0
          if italic:
              format += 1
          if bold:
              format += 2
          if format:
              bookmark.update({NameObject('/F'): NumberObject(format)})
  
          bookmarkRef = self._addObject(bookmark)
  
          parent = parent.getObject()
          parent.addChild(bookmarkRef, self)
  
          return bookmarkRef
  
      def addNamedDestinationObject(self, dest):
          destRef = self._addObject(dest)
  
          nd = self.getNamedDestRoot()
          nd.extend([dest['/Title'], destRef])
  
          return destRef
  
      def addNamedDestination(self, title, pagenum):
          pageRef = self.getObject(self._pages)['/Kids'][pagenum]
          dest = DictionaryObject()
          dest.update({
              NameObject('/D') : ArrayObject([pageRef, NameObject('/FitH'), NumberObject(826)]),
              NameObject('/S') : NameObject('/GoTo')
          })
  
          destRef = self._addObject(dest)
          nd = self.getNamedDestRoot()
  
          nd.extend([title, destRef])
  
          return destRef
  
      def removeLinks(self):
          """
          Removes links and annotations from this output.
          """
          pages = self.getObject(self._pages)['/Kids']
          for page in pages:
              pageRef = self.getObject(page)
              if "/Annots" in pageRef:
                  del pageRef['/Annots']
  
      def removeImages(self, ignoreByteStringObject=False):
          """
          Removes images from this output.
  
          :param bool ignoreByteStringObject: optional parameter
              to ignore ByteString Objects.
          """
          pages = self.getObject(self._pages)['/Kids']
          for j in range(len(pages)):
              page = pages[j]
              pageRef = self.getObject(page)
              content = pageRef['/Contents'].getObject()
              if not isinstance(content, ContentStream):
                  content = ContentStream(content, pageRef)
  
              _operations = []
              seq_graphics = False
              for operands, operator in content.operations:
                  if operator == b_('Tj'):
                      text = operands[0]
                      if ignoreByteStringObject:
                          if not isinstance(text, TextStringObject):
                              operands[0] = TextStringObject()
                  elif operator == b_("'"):
                      text = operands[0]
                      if ignoreByteStringObject:
                          if not isinstance(text, TextStringObject):
                              operands[0] = TextStringObject()
                  elif operator == b_('"'):
                      text = operands[2]
                      if ignoreByteStringObject:
                          if not isinstance(text, TextStringObject):
                              operands[2] = TextStringObject()
                  elif operator == b_("TJ"):
                      for i in range(len(operands[0])):
                          if ignoreByteStringObject:
                              if not isinstance(operands[0][i], TextStringObject):
                                  operands[0][i] = TextStringObject()
  
                  if operator == b_('q'):
                      seq_graphics = True
                  if operator == b_('Q'):
                      seq_graphics = False
                  if seq_graphics:
                      if operator in [b_('cm'), b_('w'), b_('J'), b_('j'), b_('M'), b_('d'), b_('ri'), b_('i'),
                              b_('gs'), b_('W'), b_('b'), b_('s'), b_('S'), b_('f'), b_('F'), b_('n'), b_('m'), b_('l'),
                              b_('c'), b_('v'), b_('y'), b_('h'), b_('B'), b_('Do'), b_('sh')]:
                          continue
                  if operator == b_('re'):
                      continue
                  _operations.append((operands, operator))
  
              content.operations = _operations
              pageRef.__setitem__(NameObject('/Contents'), content)
  
      def removeText(self, ignoreByteStringObject=False):
          """
          Removes images from this output.
  
          :param bool ignoreByteStringObject: optional parameter
              to ignore ByteString Objects.
          """
          pages = self.getObject(self._pages)['/Kids']
          for j in range(len(pages)):
              page = pages[j]
              pageRef = self.getObject(page)
              content = pageRef['/Contents'].getObject()
              if not isinstance(content, ContentStream):
                  content = ContentStream(content, pageRef)
              for operands,operator in content.operations:
                  if operator == b_('Tj'):
                      text = operands[0]
                      if not ignoreByteStringObject:
                          if isinstance(text, TextStringObject):
                              operands[0] = TextStringObject()
                      else:
                          if isinstance(text, TextStringObject) or \
                                  isinstance(text, ByteStringObject):
                              operands[0] = TextStringObject()
                  elif operator == b_("'"):
                      text = operands[0]
                      if not ignoreByteStringObject:
                          if isinstance(text, TextStringObject):
                              operands[0] = TextStringObject()
                      else:
                          if isinstance(text, TextStringObject) or \
                                  isinstance(text, ByteStringObject):
                              operands[0] = TextStringObject()
                  elif operator == b_('"'):
                      text = operands[2]
                      if not ignoreByteStringObject:
                          if isinstance(text, TextStringObject):
                              operands[2] = TextStringObject()
                      else:
                          if isinstance(text, TextStringObject) or \
                                  isinstance(text, ByteStringObject):
                              operands[2] = TextStringObject()
                  elif operator == b_("TJ"):
                      for i in range(len(operands[0])):
                          if not ignoreByteStringObject:
                              if isinstance(operands[0][i], TextStringObject):
                                  operands[0][i] = TextStringObject()
                          else:
                              if isinstance(operands[0][i], TextStringObject) or \
                                      isinstance(operands[0][i], ByteStringObject):
                                  operands[0][i] = TextStringObject()
  
              pageRef.__setitem__(NameObject('/Contents'), content)
  
      def addLink(self, pagenum, pagedest, rect, border=None, fit='/Fit', *args):
          """
          Add an internal link from a rectangular area to the specified page.
  
          :param int pagenum: index of the page on which to place the link.
          :param int pagedest: index of the page to which the link should go.
          :param rect: :class:`RectangleObject<PyPDF2.generic.RectangleObject>` or array of four
              integers specifying the clickable rectangular area
              ``[xLL, yLL, xUR, yUR]``, or string in the form ``"[ xLL yLL xUR yUR ]"``.
          :param border: if provided, an array describing border-drawing
              properties. See the PDF spec for details. No border will be
              drawn if this argument is omitted.
          :param str fit: Page fit or 'zoom' option (see below). Additional arguments may need
              to be supplied. Passing ``None`` will be read as a null value for that coordinate.
  
          Valid zoom arguments (see Table 8.2 of the PDF 1.7 reference for details):
               /Fit       No additional arguments
               /XYZ       [left] [top] [zoomFactor]
               /FitH      [top]
               /FitV      [left]
               /FitR      [left] [bottom] [right] [top]
               /FitB      No additional arguments
               /FitBH     [top]
               /FitBV     [left]
          """
  
          pageLink = self.getObject(self._pages)['/Kids'][pagenum]
          pageDest = self.getObject(self._pages)['/Kids'][pagedest] #TODO: switch for external link
          pageRef = self.getObject(pageLink)
  
          if border is not None:
              borderArr = [NameObject(n) for n in border[:3]]
              if len(border) == 4:
                  dashPattern = ArrayObject([NameObject(n) for n in border[3]])
                  borderArr.append(dashPattern)
          else:
              borderArr = [NumberObject(0)] * 3
  
          if isString(rect):
              rect = NameObject(rect)
          elif isinstance(rect, RectangleObject):
              pass
          else:
              rect = RectangleObject(rect)
  
          zoomArgs = []
          for a in args:
              if a is not None:
                  zoomArgs.append(NumberObject(a))
              else:
                  zoomArgs.append(NullObject())
          dest = Destination(NameObject("/LinkName"), pageDest, NameObject(fit), *zoomArgs) #TODO: create a better name for the link
          destArray = dest.getDestArray()
  
          lnk = DictionaryObject()
          lnk.update({
              NameObject('/Type'): NameObject('/Annot'),
              NameObject('/Subtype'): NameObject('/Link'),
              NameObject('/P'): pageLink,
              NameObject('/Rect'): rect,
              NameObject('/Border'): ArrayObject(borderArr),
              NameObject('/Dest'): destArray
          })
          lnkRef = self._addObject(lnk)
  
          if "/Annots" in pageRef:
              pageRef['/Annots'].append(lnkRef)
          else:
              pageRef[NameObject('/Annots')] = ArrayObject([lnkRef])
  
      _valid_layouts = ['/NoLayout', '/SinglePage', '/OneColumn', '/TwoColumnLeft', '/TwoColumnRight', '/TwoPageLeft', '/TwoPageRight']
  
      def getPageLayout(self):
          """
          Get the page layout.
          See :meth:`setPageLayout()<PdfFileWriter.setPageLayout>` for a description of valid layouts.
  
          :return: Page layout currently being used.
          :rtype: str, None if not specified
          """
          try:
              return self._root_object['/PageLayout']
          except KeyError:
              return None
  
      def setPageLayout(self, layout):
          """
          Set the page layout
  
          :param str layout: The page layout to be used
  
          Valid layouts are:
               /NoLayout        Layout explicitly not specified
               /SinglePage      Show one page at a time
               /OneColumn       Show one column at a time
               /TwoColumnLeft   Show pages in two columns, odd-numbered pages on the left
               /TwoColumnRight  Show pages in two columns, odd-numbered pages on the right
               /TwoPageLeft     Show two pages at a time, odd-numbered pages on the left
               /TwoPageRight    Show two pages at a time, odd-numbered pages on the right
          """
          if not isinstance(layout, NameObject):
              if layout not in self._valid_layouts:
                  warnings.warn("Layout should be one of: {}".format(', '.join(self._valid_layouts)))
              layout = NameObject(layout)
          self._root_object.update({NameObject('/PageLayout'): layout})
  
      pageLayout = property(getPageLayout, setPageLayout)
      """Read and write property accessing the :meth:`getPageLayout()<PdfFileWriter.getPageLayout>`
      and :meth:`setPageLayout()<PdfFileWriter.setPageLayout>` methods."""
  
      _valid_modes = ['/UseNone', '/UseOutlines', '/UseThumbs', '/FullScreen', '/UseOC', '/UseAttachments']
  
      def getPageMode(self):
          """
          Get the page mode.
          See :meth:`setPageMode()<PdfFileWriter.setPageMode>` for a description
          of valid modes.
  
          :return: Page mode currently being used.
          :rtype: str, None if not specified
          """
          try:
              return self._root_object['/PageMode']
          except KeyError:
              return None
  
      def setPageMode(self, mode):
          """
          Set the page mode.
  
          :param str mode: The page mode to use.
  
          Valid modes are:
              /UseNone         Do not show outlines or thumbnails panels
              /UseOutlines     Show outlines (aka bookmarks) panel
              /UseThumbs       Show page thumbnails panel
              /FullScreen      Fullscreen view
              /UseOC           Show Optional Content Group (OCG) panel
              /UseAttachments  Show attachments panel
          """
          if not isinstance(mode, NameObject):
              if mode not in self._valid_modes:
                  warnings.warn("Mode should be one of: {}".format(', '.join(self._valid_modes)))
              mode = NameObject(mode)
          self._root_object.update({NameObject('/PageMode'): mode})
  
      pageMode = property(getPageMode, setPageMode)
      """Read and write property accessing the :meth:`getPageMode()<PdfFileWriter.getPageMode>`
      and :meth:`setPageMode()<PdfFileWriter.setPageMode>` methods."""
  
  
  class PdfFileReader(object):
      """
      Initializes a PdfFileReader object.  This operation can take some time, as
      the PDF stream's cross-reference tables are read into memory.
  
      :param stream: A File object or an object that supports the standard read
          and seek methods similar to a File object. Could also be a
          string representing a path to a PDF file.
      :param bool strict: Determines whether user should be warned of all
          problems and also causes some correctable problems to be fatal.
          Defaults to ``True``.
      :param warndest: Destination for logging warnings (defaults to
          ``sys.stderr``).
      :param bool overwriteWarnings: Determines whether to override Python's
          ``warnings.py`` module with a custom implementation (defaults to
          ``True``).
      """
      def __init__(self, stream, strict=True, warndest = None, overwriteWarnings = True):
          if overwriteWarnings:
              # have to dynamically override the default showwarning since there are no
              # public methods that specify the 'file' parameter
              def _showwarning(message, category, filename, lineno, file=warndest, line=None):
                  if file is None:
                      file = sys.stderr
                  try:
                      file.write(formatWarning(message, category, filename, lineno, line))
                  except IOError:
                      pass
              warnings.showwarning = _showwarning
          self.strict = strict
          self.flattenedPages = None
          self.resolvedObjects = {}
          self.xrefIndex = 0
          self._pageId2Num = None # map page IndirectRef number to Page Number
          if hasattr(stream, 'mode') and 'b' not in stream.mode:
              warnings.warn("PdfFileReader stream/file object is not in binary mode. It may not be read correctly.", utils.PdfReadWarning)
          if isString(stream):
              fileobj = open(stream, 'rb')
              stream = BytesIO(b_(fileobj.read()))
              fileobj.close()
          self.read(stream)
          self.stream = stream
  
          self._override_encryption = False
  
      def getDocumentInfo(self):
          """
          Retrieves the PDF file's document information dictionary, if it exists.
          Note that some PDF files use metadata streams instead of docinfo
          dictionaries, and these metadata streams will not be accessed by this
          function.
  
          :return: the document information of this PDF file
          :rtype: :class:`DocumentInformation<pdf.DocumentInformation>` or ``None`` if none exists.
          """
          if "/Info" not in self.trailer:
              return None
          obj = self.trailer['/Info']
          retval = DocumentInformation()
          retval.update(obj)
          return retval
  
      documentInfo = property(lambda self: self.getDocumentInfo(), None, None)
      """Read-only property that accesses the :meth:`getDocumentInfo()<PdfFileReader.getDocumentInfo>` function."""
  
      def getXmpMetadata(self):
          """
          Retrieves XMP (Extensible Metadata Platform) data from the PDF document
          root.
  
          :return: a :class:`XmpInformation<xmp.XmpInformation>`
              instance that can be used to access XMP metadata from the document.
          :rtype: :class:`XmpInformation<xmp.XmpInformation>` or
              ``None`` if no metadata was found on the document root.
          """
          try:
              self._override_encryption = True
              return self.trailer["/Root"].getXmpMetadata()
          finally:
              self._override_encryption = False
  
      xmpMetadata = property(lambda self: self.getXmpMetadata(), None, None)
      """
      Read-only property that accesses the
      :meth:`getXmpMetadata()<PdfFileReader.getXmpMetadata>` function.
      """
  
      def getNumPages(self):
          """
          Calculates the number of pages in this PDF file.
  
          :return: number of pages
          :rtype: int
          :raises PdfReadError: if file is encrypted and restrictions prevent
              this action.
          """
  
          # Flattened pages will not work on an Encrypted PDF;
          # the PDF file's page count is used in this case. Otherwise,
          # the original method (flattened page count) is used.
          if self.isEncrypted:
              try:
                  self._override_encryption = True
                  self.decrypt('')
                  return self.trailer["/Root"]["/Pages"]["/Count"]
              except:
                  raise utils.PdfReadError("File has not been decrypted")
              finally:
                  self._override_encryption = False
          else:
              if self.flattenedPages == None:
                  self._flatten()
              return len(self.flattenedPages)
  
      numPages = property(lambda self: self.getNumPages(), None, None)
      """
      Read-only property that accesses the
      :meth:`getNumPages()<PdfFileReader.getNumPages>` function.
      """
  
      def getPage(self, pageNumber):
          """
          Retrieves a page by number from this PDF file.
  
          :param int pageNumber: The page number to retrieve
              (pages begin at zero)
          :return: a :class:`PageObject<pdf.PageObject>` instance.
          :rtype: :class:`PageObject<pdf.PageObject>`
          """
          ## ensure that we're not trying to access an encrypted PDF
          #assert not self.trailer.has_key("/Encrypt")
          if self.flattenedPages == None:
              self._flatten()
          return self.flattenedPages[pageNumber]
  
      namedDestinations = property(lambda self:
                                    self.getNamedDestinations(), None, None)
      """
      Read-only property that accesses the
      :meth:`getNamedDestinations()<PdfFileReader.getNamedDestinations>` function.
      """
  
      # A select group of relevant field attributes. For the complete list,
      # see section 8.6.2 of the PDF 1.7 reference.
  
      def getFields(self, tree = None, retval = None, fileobj = None):
          """
          Extracts field data if this PDF contains interactive form fields.
          The *tree* and *retval* parameters are for recursive use.
  
          :param fileobj: A file object (usually a text file) to write
              a report to on all interactive form fields found.
          :return: A dictionary where each key is a field name, and each
              value is a :class:`Field<PyPDF2.generic.Field>` object. By
              default, the mapping name is used for keys.
          :rtype: dict, or ``None`` if form data could not be located.
          """
          fieldAttributes = {"/FT" : "Field Type", "/Parent" : "Parent",
                         "/T" : "Field Name", "/TU" : "Alternate Field Name",
                         "/TM" : "Mapping Name", "/Ff" : "Field Flags",
                         "/V" : "Value", "/DV" : "Default Value"}
          if retval == None:
              retval = {}
              catalog = self.trailer["/Root"]
              # get the AcroForm tree
              if "/AcroForm" in catalog:
                  tree = catalog["/AcroForm"]
              else:
                  return None
          if tree == None:
              return retval
  
          self._checkKids(tree, retval, fileobj)
          for attr in fieldAttributes:
              if attr in tree:
                  # Tree is a field
                  self._buildField(tree, retval, fileobj, fieldAttributes)
                  break
  
          if "/Fields" in tree:
              fields = tree["/Fields"]
              for f in fields:
                  field = f.getObject()
                  self._buildField(field, retval, fileobj, fieldAttributes)
  
          return retval
  
      def _buildField(self, field, retval, fileobj, fieldAttributes):
          self._checkKids(field, retval, fileobj)
          try:
              key = field["/TM"]
          except KeyError:
              try:
                  key = field["/T"]
              except KeyError:
                  # Ignore no-name field for now
                  return
          if fileobj:
              self._writeField(fileobj, field, fieldAttributes)
              fileobj.write("\n")
          retval[key] = Field(field)
  
      def _checkKids(self, tree, retval, fileobj):
          if "/Kids" in tree:
              # recurse down the tree
              for kid in tree["/Kids"]:
                  self.getFields(kid.getObject(), retval, fileobj)
  
      def _writeField(self, fileobj, field, fieldAttributes):
          order = ["/TM", "/T", "/FT", "/Parent", "/TU", "/Ff", "/V", "/DV"]
          for attr in order:
              attrName = fieldAttributes[attr]
              try:
                  if attr == "/FT":
                      # Make the field type value more clear
                      types = {"/Btn":"Button", "/Tx":"Text", "/Ch": "Choice",
                               "/Sig":"Signature"}
                      if field[attr] in types:
                          fileobj.write(attrName + ": " + types[field[attr]] + "\n")
                  elif attr == "/Parent":
                      # Let's just write the name of the parent
                      try:
                          name = field["/Parent"]["/TM"]
                      except KeyError:
                          name = field["/Parent"]["/T"]
                      fileobj.write(attrName + ": " + name + "\n")
                  else:
                      fileobj.write(attrName + ": " + str(field[attr]) + "\n")
              except KeyError:
                  # Field attribute is N/A or unknown, so don't write anything
                  pass
  
      def getFormTextFields(self):
          ''' Retrieves form fields from the document with textual data (inputs, dropdowns)
          '''
          # Retrieve document form fields
          formfields = self.getFields()
          return dict(
              (formfields[field]['/T'], formfields[field].get('/V')) for field in formfields \
                  if formfields[field].get('/FT') == '/Tx'
          )
  
      def getNamedDestinations(self, tree=None, retval=None):
          """
          Retrieves the named destinations present in the document.
  
          :return: a dictionary which maps names to
              :class:`Destinations<PyPDF2.generic.Destination>`.
          :rtype: dict
          """
          if retval == None:
              retval = {}
              catalog = self.trailer["/Root"]
  
              # get the name tree
              if "/Dests" in catalog:
                  tree = catalog["/Dests"]
              elif "/Names" in catalog:
                  names = catalog['/Names']
                  if "/Dests" in names:
                      tree = names['/Dests']
  
          if tree == None:
              return retval
  
          if "/Kids" in tree:
              # recurse down the tree
              for kid in tree["/Kids"]:
                  self.getNamedDestinations(kid.getObject(), retval)
  
          if "/Names" in tree:
              names = tree["/Names"]
              for i in range(0, len(names), 2):
                  key = names[i].getObject()
                  val = names[i+1].getObject()
                  if isinstance(val, DictionaryObject) and '/D' in val:
                      val = val['/D']
                  dest = self._buildDestination(key, val)
                  if dest != None:
                      retval[key] = dest
  
          return retval
  
      outlines = property(lambda self: self.getOutlines(), None, None)
      """
      Read-only property that accesses the
          :meth:`getOutlines()<PdfFileReader.getOutlines>` function.
      """
  
      def getOutlines(self, node=None, outlines=None):
          """
          Retrieves the document outline present in the document.
  
          :return: a nested list of :class:`Destinations<PyPDF2.generic.Destination>`.
          """
          if outlines == None:
              outlines = []
              catalog = self.trailer["/Root"]
  
              # get the outline dictionary and named destinations
              if "/Outlines" in catalog:
                  try:
                      lines = catalog["/Outlines"]
                  except utils.PdfReadError:
                      # this occurs if the /Outlines object reference is incorrect
                      # for an example of such a file, see https://unglueit-files.s3.amazonaws.com/ebf/7552c42e9280b4476e59e77acc0bc812.pdf
                      # so continue to load the file without the Bookmarks
                      return outlines
  
                  if "/First" in lines:
                      node = lines["/First"]
              self._namedDests = self.getNamedDestinations()
  
          if node == None:
            return outlines
  
          # see if there are any more outlines
          while True:
              outline = self._buildOutline(node)
              if outline:
                  outlines.append(outline)
  
              # check for sub-outlines
              if "/First" in node:
                  subOutlines = []
                  self.getOutlines(node["/First"], subOutlines)
                  if subOutlines:
                      outlines.append(subOutlines)
  
              if "/Next" not in node:
                  break
              node = node["/Next"]
  
          return outlines
  
      def _getPageNumberByIndirect(self, indirectRef):
          """Generate _pageId2Num"""
          if self._pageId2Num is None:
              id2num = {}
              for i, x in enumerate(self.pages):
                  id2num[x.indirectRef.idnum] = i
              self._pageId2Num = id2num
  
          if isinstance(indirectRef, int):
              idnum = indirectRef
          else:
              idnum = indirectRef.idnum
  
          ret = self._pageId2Num.get(idnum, -1)
          return ret
  
      def getPageNumber(self, page):
          """
          Retrieve page number of a given PageObject
  
          :param PageObject page: The page to get page number. Should be
              an instance of :class:`PageObject<PyPDF2.pdf.PageObject>`
          :return: the page number or -1 if page not found
          :rtype: int
          """
          indirectRef = page.indirectRef
          ret = self._getPageNumberByIndirect(indirectRef)
          return ret
  
      def getDestinationPageNumber(self, destination):
          """
          Retrieve page number of a given Destination object
  
          :param Destination destination: The destination to get page number.
               Should be an instance of
               :class:`Destination<PyPDF2.pdf.Destination>`
          :return: the page number or -1 if page not found
          :rtype: int
          """
          indirectRef = destination.page
          ret = self._getPageNumberByIndirect(indirectRef)
          return ret
  
      def _buildDestination(self, title, array):
          page, typ = array[0:2]
          array = array[2:]
          return Destination(title, page, typ, *array)
  
      def _buildOutline(self, node):
          dest, title, outline = None, None, None
  
          if "/A" in node and "/Title" in node:
              # Action, section 8.5 (only type GoTo supported)
              title  = node["/Title"]
              action = node["/A"]
              if action["/S"] == "/GoTo":
                  dest = action["/D"]
          elif "/Dest" in node and "/Title" in node:
              # Destination, section 8.2.1
              title = node["/Title"]
              dest  = node["/Dest"]
  
          # if destination found, then create outline
          if dest:
              if isinstance(dest, ArrayObject):
                  outline = self._buildDestination(title, dest)
              elif isString(dest) and dest in self._namedDests:
                  outline = self._namedDests[dest]
                  outline[NameObject("/Title")] = title
              else:
                  raise utils.PdfReadError("Unexpected destination %r" % dest)
          return outline
  
      pages = property(lambda self: ConvertFunctionsToVirtualList(self.getNumPages, self.getPage),
          None, None)
      """
      Read-only property that emulates a list based upon the
      :meth:`getNumPages()<PdfFileReader.getNumPages>` and
      :meth:`getPage()<PdfFileReader.getPage>` methods.
      """
  
      def getPageLayout(self):
          """
          Get the page layout.
          See :meth:`setPageLayout()<PdfFileWriter.setPageLayout>`
          for a description of valid layouts.
  
          :return: Page layout currently being used.
          :rtype: ``str``, ``None`` if not specified
          """
          try:
              return self.trailer['/Root']['/PageLayout']
          except KeyError:
              return None
  
      pageLayout = property(getPageLayout)
      """Read-only property accessing the
      :meth:`getPageLayout()<PdfFileReader.getPageLayout>` method."""
  
      def getPageMode(self):
          """
          Get the page mode.
          See :meth:`setPageMode()<PdfFileWriter.setPageMode>`
          for a description of valid modes.
  
          :return: Page mode currently being used.
          :rtype: ``str``, ``None`` if not specified
          """
          try:
              return self.trailer['/Root']['/PageMode']
          except KeyError:
              return None
  
      pageMode = property(getPageMode)
      """Read-only property accessing the
      :meth:`getPageMode()<PdfFileReader.getPageMode>` method."""
  
      def _flatten(self, pages=None, inherit=None, indirectRef=None):
          inheritablePageAttributes = (
              NameObject("/Resources"), NameObject("/MediaBox"),
              NameObject("/CropBox"), NameObject("/Rotate")
              )
          if inherit == None:
              inherit = dict()
          if pages == None:
              self.flattenedPages = []
              catalog = self.trailer["/Root"].getObject()
              pages = catalog["/Pages"].getObject()
  
          t = "/Pages"
          if "/Type" in pages:
              t = pages["/Type"]
  
          if t == "/Pages":
              for attr in inheritablePageAttributes:
                  if attr in pages:
                      inherit[attr] = pages[attr]
              for page in pages["/Kids"]:
                  addt = {}
                  if isinstance(page, IndirectObject):
                      addt["indirectRef"] = page
                  self._flatten(page.getObject(), inherit, **addt)
          elif t == "/Page":
              for attr, value in list(inherit.items()):
                  # if the page has it's own value, it does not inherit the
                  # parent's value:
                  if attr not in pages:
                      pages[attr] = value
              pageObj = PageObject(self, indirectRef)
              pageObj.update(pages)
              self.flattenedPages.append(pageObj)
  
      def _getObjectFromStream(self, indirectReference):
          # indirect reference to object in object stream
          # read the entire object stream into memory
          debug = False
          stmnum, idx = self.xref_objStm[indirectReference.idnum]
          if debug: print(("Here1: %s %s"%(stmnum, idx)))
          objStm = IndirectObject(stmnum, 0, self).getObject()
          if debug: print(("Here2: objStm=%s.. stmnum=%s data=%s"%(objStm, stmnum, objStm.getData())))
          # This is an xref to a stream, so its type better be a stream
          assert objStm['/Type'] == '/ObjStm'
          # /N is the number of indirect objects in the stream
          assert idx < objStm['/N']
          streamData = BytesIO(b_(objStm.getData()))
          for i in range(objStm['/N']):
              readNonWhitespace(streamData)
              streamData.seek(-1, 1)
              objnum = NumberObject.readFromStream(streamData)
              readNonWhitespace(streamData)
              streamData.seek(-1, 1)
              offset = NumberObject.readFromStream(streamData)
              readNonWhitespace(streamData)
              streamData.seek(-1, 1)
              if objnum != indirectReference.idnum:
                  # We're only interested in one object
                  continue
              if self.strict and idx != i:
                  raise utils.PdfReadError("Object is in wrong index.")
              streamData.seek(objStm['/First']+offset, 0)
              if debug:
                  pos = streamData.tell()
                  streamData.seek(0, 0)
                  lines = streamData.readlines()
                  for i in range(0, len(lines)):
                      print((lines[i]))
                  streamData.seek(pos, 0)
              try:
                  obj = readObject(streamData, self)
              except utils.PdfStreamError as e:
                  # Stream object cannot be read. Normally, a critical error, but
                  # Adobe Reader doesn't complain, so continue (in strict mode?)
                  e = sys.exc_info()[1]
                  warnings.warn("Invalid stream (index %d) within object %d %d: %s" % \
                        (i, indirectReference.idnum, indirectReference.generation, e), utils.PdfReadWarning)
  
                  if self.strict:
                      raise utils.PdfReadError("Can't read object stream: %s"%e)
                  # Replace with null. Hopefully it's nothing important.
                  obj = NullObject()
              return obj
  
          if self.strict: raise utils.PdfReadError("This is a fatal error in strict mode.")
          return NullObject()
  
      def getObject(self, indirectReference):
          debug = False
          if debug: print(("looking at:", indirectReference.idnum, indirectReference.generation))
          retval = self.cacheGetIndirectObject(indirectReference.generation,
                                                  indirectReference.idnum)
          if retval != None:
              return retval
          if indirectReference.generation == 0 and \
                          indirectReference.idnum in self.xref_objStm:
              retval = self._getObjectFromStream(indirectReference)
          elif indirectReference.generation in self.xref and \
                  indirectReference.idnum in self.xref[indirectReference.generation]:
              start = self.xref[indirectReference.generation][indirectReference.idnum]
              if debug: print(("  Uncompressed Object", indirectReference.idnum, indirectReference.generation, ":", start))
              self.stream.seek(start, 0)
              idnum, generation = self.readObjectHeader(self.stream)
              if idnum != indirectReference.idnum and self.xrefIndex:
                  # Xref table probably had bad indexes due to not being zero-indexed
                  if self.strict:
                      raise utils.PdfReadError("Expected object ID (%d %d) does not match actual (%d %d); xref table not zero-indexed." \
                                       % (indirectReference.idnum, indirectReference.generation, idnum, generation))
                  else: pass # xref table is corrected in non-strict mode
              elif idnum != indirectReference.idnum:
                  # some other problem
                  raise utils.PdfReadError("Expected object ID (%d %d) does not match actual (%d %d)." \
                                           % (indirectReference.idnum, indirectReference.generation, idnum, generation))
              assert generation == indirectReference.generation
              retval = readObject(self.stream, self)
  
              # override encryption is used for the /Encrypt dictionary
              if not self._override_encryption and self.isEncrypted:
                  # if we don't have the encryption key:
                  if not hasattr(self, '_decryption_key'):
                      raise utils.PdfReadError("file has not been decrypted")
                  # otherwise, decrypt here...
                  import struct
                  pack1 = struct.pack("<i", indirectReference.idnum)[:3]
                  pack2 = struct.pack("<i", indirectReference.generation)[:2]
                  key = self._decryption_key + pack1 + pack2
                  assert len(key) == (len(self._decryption_key) + 5)
                  md5_hash = md5(key).digest()
                  key = md5_hash[:min(16, len(self._decryption_key) + 5)]
                  retval = self._decryptObject(retval, key)
          else:
              warnings.warn("Object %d %d not defined."%(indirectReference.idnum,
                          indirectReference.generation), utils.PdfReadWarning)
              #if self.strict:
              raise utils.PdfReadError("Could not find object.")
          self.cacheIndirectObject(indirectReference.generation,
                      indirectReference.idnum, retval)
          return retval
  
      def _decryptObject(self, obj, key):
          if isinstance(obj, ByteStringObject) or isinstance(obj, TextStringObject):
              obj = createStringObject(utils.RC4_encrypt(key, obj.original_bytes))
          elif isinstance(obj, StreamObject):
              obj._data = utils.RC4_encrypt(key, obj._data)
          elif isinstance(obj, DictionaryObject):
              for dictkey, value in list(obj.items()):
                  obj[dictkey] = self._decryptObject(value, key)
          elif isinstance(obj, ArrayObject):
              for i in range(len(obj)):
                  obj[i] = self._decryptObject(obj[i], key)
          return obj
  
      def readObjectHeader(self, stream):
          # Should never be necessary to read out whitespace, since the
          # cross-reference table should put us in the right spot to read the
          # object header.  In reality... some files have stupid cross reference
          # tables that are off by whitespace bytes.
          extra = False
          utils.skipOverComment(stream)
          extra |= utils.skipOverWhitespace(stream); stream.seek(-1, 1)
          idnum = readUntilWhitespace(stream)
          extra |= utils.skipOverWhitespace(stream); stream.seek(-1, 1)
          generation = readUntilWhitespace(stream)
          obj = stream.read(3)
          readNonWhitespace(stream)
          stream.seek(-1, 1)
          if (extra and self.strict):
              #not a fatal error
              warnings.warn("Superfluous whitespace found in object header %s %s" % \
                            (idnum, generation), utils.PdfReadWarning)
          return int(idnum), int(generation)
  
      def cacheGetIndirectObject(self, generation, idnum):
          debug = False
          out = self.resolvedObjects.get((generation, idnum))
          if debug and out: print(("cache hit: %d %d"%(idnum, generation)))
          elif debug: print(("cache miss: %d %d"%(idnum, generation)))
          return out
  
      def cacheIndirectObject(self, generation, idnum, obj):
          # return None # Sometimes we want to turn off cache for debugging.
          if (generation, idnum) in self.resolvedObjects:
              msg = "Overwriting cache for %s %s"%(generation, idnum)
              if self.strict: raise utils.PdfReadError(msg)
              else:           warnings.warn(msg)
          self.resolvedObjects[(generation, idnum)] = obj
          return obj
  
      def read(self, stream):
          debug = False
          if debug: print(">>read", stream)
          # start at the end:
          stream.seek(-1, 2)
          if not stream.tell():
              raise utils.PdfReadError('Cannot read an empty file')
          last1K = stream.tell() - 1024 + 1 # offset of last 1024 bytes of stream
          line = b_('')
          while line[:5] != b_("%%EOF"):
              if stream.tell() < last1K:
                  raise utils.PdfReadError("EOF marker not found")
              line = self.readNextEndLine(stream)
              if debug: print("  line:",line)
  
          # find startxref entry - the location of the xref table
          line = self.readNextEndLine(stream)
          try:
              startxref = int(line)
          except ValueError:
              # 'startxref' may be on the same line as the location
              if not line.startswith(b_("startxref")):
                  raise utils.PdfReadError("startxref not found")
              startxref = int(line[9:].strip())
              warnings.warn("startxref on same line as offset")
          else:
              line = self.readNextEndLine(stream)
              if line[:9] != b_("startxref"):
                  raise utils.PdfReadError("startxref not found")
  
          # read all cross reference tables and their trailers
          self.xref = {}
          self.xref_objStm = {}
          self.trailer = DictionaryObject()
          while True:
              # load the xref table
              stream.seek(startxref, 0)
              x = stream.read(1)
              if x == b_("x"):
                  # standard cross-reference table
                  ref = stream.read(4)
                  if ref[:3] != b_("ref"):
                      raise utils.PdfReadError("xref table read error")
                  readNonWhitespace(stream)
                  stream.seek(-1, 1)
                  firsttime = True; # check if the first time looking at the xref table
                  while True:
                      num = readObject(stream, self)
                      if firsttime and num != 0:
                           self.xrefIndex = num
                           if self.strict:
                              warnings.warn("Xref table not zero-indexed. ID numbers for objects will be corrected.", utils.PdfReadWarning)
                              #if table not zero indexed, could be due to error from when PDF was created
                              #which will lead to mismatched indices later on, only warned and corrected if self.strict=True
                      firsttime = False
                      readNonWhitespace(stream)
                      stream.seek(-1, 1)
                      size = readObject(stream, self)
                      readNonWhitespace(stream)
                      stream.seek(-1, 1)
                      cnt = 0
                      while cnt < size:
                          line = stream.read(20)
  
                          # It's very clear in section 3.4.3 of the PDF spec
                          # that all cross-reference table lines are a fixed
                          # 20 bytes (as of PDF 1.7). However, some files have
                          # 21-byte entries (or more) due to the use of \r\n
                          # (CRLF) EOL's. Detect that case, and adjust the line
                          # until it does not begin with a \r (CR) or \n (LF).
                          while line[0] in b_("\x0D\x0A"):
                              stream.seek(-20 + 1, 1)
                              line = stream.read(20)
  
                          # On the other hand, some malformed PDF files
                          # use a single character EOL without a preceeding
                          # space.  Detect that case, and seek the stream
                          # back one character.  (0-9 means we've bled into
                          # the next xref entry, t means we've bled into the
                          # text "trailer"):
                          if line[-1] in b_("0123456789t"):
                              stream.seek(-1, 1)
  
                          offset, generation = line[:16].split(b_(" "))
                          offset, generation = int(offset), int(generation)
                          if generation not in self.xref:
                              self.xref[generation] = {}
                          if num in self.xref[generation]:
                              # It really seems like we should allow the last
                              # xref table in the file to override previous
                              # ones. Since we read the file backwards, assume
                              # any existing key is already set correctly.
                              pass
                          else:
                              self.xref[generation][num] = offset
                          cnt += 1
                          num += 1
                      readNonWhitespace(stream)
                      stream.seek(-1, 1)
                      trailertag = stream.read(7)
                      if trailertag != b_("trailer"):
                          # more xrefs!
                          stream.seek(-7, 1)
                      else:
                          break
                  readNonWhitespace(stream)
                  stream.seek(-1, 1)
                  newTrailer = readObject(stream, self)
                  for key, value in list(newTrailer.items()):
                      if key not in self.trailer:
                          self.trailer[key] = value
                  if "/Prev" in newTrailer:
                      startxref = newTrailer["/Prev"]
                  else:
                      break
              elif x.isdigit():
                  # PDF 1.5+ Cross-Reference Stream
                  stream.seek(-1, 1)
                  idnum, generation = self.readObjectHeader(stream)
                  xrefstream = readObject(stream, self)
                  assert xrefstream["/Type"] == "/XRef"
                  self.cacheIndirectObject(generation, idnum, xrefstream)
                  streamData = BytesIO(b_(xrefstream.getData()))
                  # Index pairs specify the subsections in the dictionary. If
                  # none create one subsection that spans everything.
                  idx_pairs = xrefstream.get("/Index", [0, xrefstream.get("/Size")])
                  if debug: print(("read idx_pairs=%s"%list(self._pairs(idx_pairs))))
                  entrySizes = xrefstream.get("/W")
                  assert len(entrySizes) >= 3
                  if self.strict and len(entrySizes) > 3:
                      raise utils.PdfReadError("Too many entry sizes: %s" %entrySizes)
  
                  def getEntry(i):
                      # Reads the correct number of bytes for each entry. See the
                      # discussion of the W parameter in PDF spec table 17.
                      if entrySizes[i] > 0:
                          d = streamData.read(entrySizes[i])
                          return convertToInt(d, entrySizes[i])
  
                      # PDF Spec Table 17: A value of zero for an element in the
                      # W array indicates...the default value shall be used
                      if i == 0:  return 1 # First value defaults to 1
                      else:       return 0
  
                  def used_before(num, generation):
                      # We move backwards through the xrefs, don't replace any.
                      return num in self.xref.get(generation, []) or \
                              num in self.xref_objStm
  
                  # Iterate through each subsection
                  last_end = 0
                  for start, size in self._pairs(idx_pairs):
                      # The subsections must increase
                      assert start >= last_end
                      last_end = start + size
                      for num in range(start, start+size):
                          # The first entry is the type
                          xref_type = getEntry(0)
                          # The rest of the elements depend on the xref_type
                          if xref_type == 0:
                              # linked list of free objects
                              next_free_object = getEntry(1)
                              next_generation = getEntry(2)
                          elif xref_type == 1:
                              # objects that are in use but are not compressed
                              byte_offset = getEntry(1)
                              generation = getEntry(2)
                              if generation not in self.xref:
                                  self.xref[generation] = {}
                              if not used_before(num, generation):
                                  self.xref[generation][num] = byte_offset
                                  if debug: print(("XREF Uncompressed: %s %s"%(
                                                  num, generation)))
                          elif xref_type == 2:
                              # compressed objects
                              objstr_num = getEntry(1)
                              obstr_idx = getEntry(2)
                              generation = 0 # PDF spec table 18, generation is 0
                              if not used_before(num, generation):
                                  if debug: print(("XREF Compressed: %s %s %s"%(
                                          num, objstr_num, obstr_idx)))
                                  self.xref_objStm[num] = (objstr_num, obstr_idx)
                          elif self.strict:
                              raise utils.PdfReadError("Unknown xref type: %s"%
                                                          xref_type)
  
                  trailerKeys = "/Root", "/Encrypt", "/Info", "/ID"
                  for key in trailerKeys:
                      if key in xrefstream and key not in self.trailer:
                          self.trailer[NameObject(key)] = xrefstream.raw_get(key)
                  if "/Prev" in xrefstream:
                      startxref = xrefstream["/Prev"]
                  else:
                      break
              else:
                  # bad xref character at startxref.  Let's see if we can find
                  # the xref table nearby, as we've observed this error with an
                  # off-by-one before.
                  stream.seek(-11, 1)
                  tmp = stream.read(20)
                  xref_loc = tmp.find(b_("xref"))
                  if xref_loc != -1:
                      startxref -= (10 - xref_loc)
                      continue
                  # No explicit xref table, try finding a cross-reference stream.
                  stream.seek(startxref, 0)
                  found = False
                  for look in range(5):
                      if stream.read(1).isdigit():
                          # This is not a standard PDF, consider adding a warning
                          startxref += look
                          found = True
                          break
                  if found:
                      continue
                  # no xref table found at specified location
                  raise utils.PdfReadError("Could not find xref table at specified location")
          #if not zero-indexed, verify that the table is correct; change it if necessary
          if self.xrefIndex and not self.strict:
              loc = stream.tell()
              for gen in self.xref:
                  if gen == 65535: continue
                  for id in self.xref[gen]:
                      stream.seek(self.xref[gen][id], 0)
                      try:
                          pid, pgen = self.readObjectHeader(stream)
                      except ValueError:
                          break
                      if pid == id - self.xrefIndex:
                          self._zeroXref(gen)
                          break
                      #if not, then either it's just plain wrong, or the non-zero-index is actually correct
              stream.seek(loc, 0) #return to where it was
  
      def _zeroXref(self, generation):
          self.xref[generation] = dict( (k-self.xrefIndex, v) for (k, v) in list(self.xref[generation].items()) )
  
      def _pairs(self, array):
          i = 0
          while True:
              yield array[i], array[i+1]
              i += 2
              if (i+1) >= len(array):
                  break
  
      def readNextEndLine(self, stream):
          debug = False
          if debug: print(">>readNextEndLine")
          line = b_("")
          while True:
              # Prevent infinite loops in malformed PDFs
              if stream.tell() == 0:
                  raise utils.PdfReadError("Could not read malformed PDF file")
              x = stream.read(1)
              if debug: print(("  x:", x, "%x"%ord(x)))
              if stream.tell() < 2:
                  raise utils.PdfReadError("EOL marker not found")
              stream.seek(-2, 1)
              if x == b_('\n') or x == b_('\r'): ## \n = LF; \r = CR
                  crlf = False
                  while x == b_('\n') or x == b_('\r'):
                      if debug:
                          if ord(x) == 0x0D: print("  x is CR 0D")
                          elif ord(x) == 0x0A: print("  x is LF 0A")
                      x = stream.read(1)
                      if x == b_('\n') or x == b_('\r'): # account for CR+LF
                          stream.seek(-1, 1)
                          crlf = True
                      if stream.tell() < 2:
                          raise utils.PdfReadError("EOL marker not found")
                      stream.seek(-2, 1)
                  stream.seek(2 if crlf else 1, 1) #if using CR+LF, go back 2 bytes, else 1
                  break
              else:
                  if debug: print("  x is neither")
                  line = x + line
                  if debug: print(("  RNEL line:", line))
          if debug: print("leaving RNEL")
          return line
  
      def decrypt(self, password):
          """
          When using an encrypted / secured PDF file with the PDF Standard
          encryption handler, this function will allow the file to be decrypted.
          It checks the given password against the document's user password and
          owner password, and then stores the resulting decryption key if either
          password is correct.
  
          It does not matter which password was matched.  Both passwords provide
          the correct decryption key that will allow the document to be used with
          this library.
  
          :param str password: The password to match.
          :return: ``0`` if the password failed, ``1`` if the password matched the user
              password, and ``2`` if the password matched the owner password.
          :rtype: int
          :raises NotImplementedError: if document uses an unsupported encryption
              method.
          """
  
          self._override_encryption = True
          try:
              return self._decrypt(password)
          finally:
              self._override_encryption = False
  
      def _decrypt(self, password):
          encrypt = self.trailer['/Encrypt'].getObject()
          if encrypt['/Filter'] != '/Standard':
              raise NotImplementedError("only Standard PDF encryption handler is available")
          if not (encrypt['/V'] in (1, 2)):
              raise NotImplementedError("only algorithm code 1 and 2 are supported")
          user_password, key = self._authenticateUserPassword(password)
          if user_password:
              self._decryption_key = key
              return 1
          else:
              rev = encrypt['/R'].getObject()
              if rev == 2:
                  keylen = 5
              else:
                  keylen = encrypt['/Length'].getObject() // 8
              key = _alg33_1(password, rev, keylen)
              real_O = encrypt["/O"].getObject()
              if rev == 2:
                  userpass = utils.RC4_encrypt(key, real_O)
              else:
                  val = real_O
                  for i in range(19, -1, -1):
                      new_key = b_('')
                      for l in range(len(key)):
                          new_key += b_(chr(utils.ord_(key[l]) ^ i))
                      val = utils.RC4_encrypt(new_key, val)
                  userpass = val
              owner_password, key = self._authenticateUserPassword(userpass)
              if owner_password:
                  self._decryption_key = key
                  return 2
          return 0
  
      def _authenticateUserPassword(self, password):
          encrypt = self.trailer['/Encrypt'].getObject()
          rev = encrypt['/R'].getObject()
          owner_entry = encrypt['/O'].getObject()
          p_entry = encrypt['/P'].getObject()
          id_entry = self.trailer['/ID'].getObject()
          id1_entry = id_entry[0].getObject()
          real_U = encrypt['/U'].getObject().original_bytes
          if rev == 2:
              U, key = _alg34(password, owner_entry, p_entry, id1_entry)
          elif rev >= 3:
              U, key = _alg35(password, rev,
                      encrypt["/Length"].getObject() // 8, owner_entry,
                      p_entry, id1_entry,
                      encrypt.get("/EncryptMetadata", BooleanObject(False)).getObject())
              U, real_U = U[:16], real_U[:16]
          return U == real_U, key
  
      def getIsEncrypted(self):
          return "/Encrypt" in self.trailer
  
      isEncrypted = property(lambda self: self.getIsEncrypted(), None, None)
      """
      Read-only boolean property showing whether this PDF file is encrypted.
      Note that this property, if true, will remain true even after the
      :meth:`decrypt()<PdfFileReader.decrypt>` method is called.
      """
  
  
  def getRectangle(self, name, defaults):
      retval = self.get(name)
      if isinstance(retval, RectangleObject):
          return retval
      if retval == None:
          for d in defaults:
              retval = self.get(d)
              if retval != None:
                  break
      if isinstance(retval, IndirectObject):
          retval = self.pdf.getObject(retval)
      retval = RectangleObject(retval)
      setRectangle(self, name, retval)
      return retval
  
  
  def setRectangle(self, name, value):
      if not isinstance(name, NameObject):
          name = NameObject(name)
      self[name] = value
  
  
  def deleteRectangle(self, name):
      del self[name]
  
  
  def createRectangleAccessor(name, fallback):
      return \
          property(
              lambda self: getRectangle(self, name, fallback),
              lambda self, value: setRectangle(self, name, value),
              lambda self: deleteRectangle(self, name)
              )
  
  
  class PageObject(DictionaryObject):
      """
      This class represents a single page within a PDF file.  Typically this
      object will be created by accessing the
      :meth:`getPage()<PyPDF2.PdfFileReader.getPage>` method of the
      :class:`PdfFileReader<PyPDF2.PdfFileReader>` class, but it is
      also possible to create an empty page with the
      :meth:`createBlankPage()<PageObject.createBlankPage>` static method.
  
      :param pdf: PDF file the page belongs to.
      :param indirectRef: Stores the original indirect reference to
          this object in its source PDF
      """
      def __init__(self, pdf=None, indirectRef=None):
          DictionaryObject.__init__(self)
          self.pdf = pdf
          self.indirectRef = indirectRef
  
      def createBlankPage(pdf=None, width=None, height=None):
          """
          Returns a new blank page.
          If ``width`` or ``height`` is ``None``, try to get the page size
          from the last page of *pdf*.
  
          :param pdf: PDF file the page belongs to
          :param float width: The width of the new page expressed in default user
              space units.
          :param float height: The height of the new page expressed in default user
              space units.
          :return: the new blank page:
          :rtype: :class:`PageObject<PageObject>`
          :raises PageSizeNotDefinedError: if ``pdf`` is ``None`` or contains
              no page
          """
          page = PageObject(pdf)
  
          # Creates a new page (cf PDF Reference  7.7.3.3)
          page.__setitem__(NameObject('/Type'), NameObject('/Page'))
          page.__setitem__(NameObject('/Parent'), NullObject())
          page.__setitem__(NameObject('/Resources'), DictionaryObject())
          if width is None or height is None:
              if pdf is not None and pdf.getNumPages() > 0:
                  lastpage = pdf.getPage(pdf.getNumPages() - 1)
                  width = lastpage.mediaBox.getWidth()
                  height = lastpage.mediaBox.getHeight()
              else:
                  raise utils.PageSizeNotDefinedError()
          page.__setitem__(NameObject('/MediaBox'),
              RectangleObject([0, 0, width, height]))
  
          return page
      createBlankPage = staticmethod(createBlankPage)
  
      def rotateClockwise(self, angle):
          """
          Rotates a page clockwise by increments of 90 degrees.
  
          :param int angle: Angle to rotate the page.  Must be an increment
              of 90 deg.
          """
          assert angle % 90 == 0
          self._rotate(angle)
          return self
  
      def rotateCounterClockwise(self, angle):
          """
          Rotates a page counter-clockwise by increments of 90 degrees.
  
          :param int angle: Angle to rotate the page.  Must be an increment
              of 90 deg.
          """
          assert angle % 90 == 0
          self._rotate(-angle)
          return self
  
      def _rotate(self, angle):
          currentAngle = self.get("/Rotate", 0)
          self[NameObject("/Rotate")] = NumberObject(currentAngle + angle)
  
      def _mergeResources(res1, res2, resource):
          newRes = DictionaryObject()
          newRes.update(res1.get(resource, DictionaryObject()).getObject())
          page2Res = res2.get(resource, DictionaryObject()).getObject()
          renameRes = {}
          for key in list(page2Res.keys()):
              if key in newRes and newRes.raw_get(key) != page2Res.raw_get(key):
                  newname = NameObject(key + str(uuid.uuid4()))
                  renameRes[key] = newname
                  newRes[newname] = page2Res[key]
              elif key not in newRes:
                  newRes[key] = page2Res.raw_get(key)
          return newRes, renameRes
      _mergeResources = staticmethod(_mergeResources)
  
      def _contentStreamRename(stream, rename, pdf):
          if not rename:
              return stream
          stream = ContentStream(stream, pdf)
          for operands, operator in stream.operations:
              for i in range(len(operands)):
                  op = operands[i]
                  if isinstance(op, NameObject):
                      operands[i] = rename.get(op,op)
          return stream
      _contentStreamRename = staticmethod(_contentStreamRename)
  
      def _pushPopGS(contents, pdf):
          # adds a graphics state "push" and "pop" to the beginning and end
          # of a content stream.  This isolates it from changes such as
          # transformation matricies.
          stream = ContentStream(contents, pdf)
          stream.operations.insert(0, [[], "q"])
          stream.operations.append([[], "Q"])
          return stream
      _pushPopGS = staticmethod(_pushPopGS)
  
      def _addTransformationMatrix(contents, pdf, ctm):
          # adds transformation matrix at the beginning of the given
          # contents stream.
          a, b, c, d, e, f = ctm
          contents = ContentStream(contents, pdf)
          contents.operations.insert(0, [[FloatObject(a), FloatObject(b),
              FloatObject(c), FloatObject(d), FloatObject(e),
              FloatObject(f)], " cm"])
          return contents
      _addTransformationMatrix = staticmethod(_addTransformationMatrix)
  
      def getContents(self):
          """
          Accesses the page contents.
  
          :return: the ``/Contents`` object, or ``None`` if it doesn't exist.
              ``/Contents`` is optional, as described in PDF Reference  7.7.3.3
          """
          if "/Contents" in self:
              return self["/Contents"].getObject()
          else:
              return None
  
      def mergePage(self, page2):
          """
          Merges the content streams of two pages into one.  Resource references
          (i.e. fonts) are maintained from both pages.  The mediabox/cropbox/etc
          of this page are not altered.  The parameter page's content stream will
          be added to the end of this page's content stream, meaning that it will
          be drawn after, or "on top" of this page.
  
          :param PageObject page2: The page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          """
          self._mergePage(page2)
  
      def _mergePage(self, page2, page2transformation=None, ctm=None, expand=False):
          # First we work on merging the resource dictionaries.  This allows us
          # to find out what symbols in the content streams we might need to
          # rename.
  
          newResources = DictionaryObject()
          rename = {}
          originalResources = self["/Resources"].getObject()
          page2Resources = page2["/Resources"].getObject()
          newAnnots = ArrayObject()
  
          for page in (self, page2):
              if "/Annots" in page:
                  annots = page["/Annots"]
                  if isinstance(annots, ArrayObject):
                      for ref in annots:
                          newAnnots.append(ref)
  
          for res in "/ExtGState", "/Font", "/XObject", "/ColorSpace", "/Pattern", "/Shading", "/Properties":
              new, newrename = PageObject._mergeResources(originalResources, page2Resources, res)
              if new:
                  newResources[NameObject(res)] = new
                  rename.update(newrename)
  
          # Combine /ProcSet sets.
          newResources[NameObject("/ProcSet")] = ArrayObject(
              frozenset(originalResources.get("/ProcSet", ArrayObject()).getObject()).union(
                  frozenset(page2Resources.get("/ProcSet", ArrayObject()).getObject())
              )
          )
  
          newContentArray = ArrayObject()
  
          originalContent = self.getContents()
          if originalContent is not None:
              newContentArray.append(PageObject._pushPopGS(
                    originalContent, self.pdf))
  
          page2Content = page2.getContents()
          if page2Content is not None:
              if page2transformation is not None:
                  page2Content = page2transformation(page2Content)
              page2Content = PageObject._contentStreamRename(
                  page2Content, rename, self.pdf)
              page2Content = PageObject._pushPopGS(page2Content, self.pdf)
              newContentArray.append(page2Content)
  
          # if expanding the page to fit a new page, calculate the new media box size
          if expand:
              corners1 = [self.mediaBox.getLowerLeft_x().as_numeric(), self.mediaBox.getLowerLeft_y().as_numeric(),
                          self.mediaBox.getUpperRight_x().as_numeric(), self.mediaBox.getUpperRight_y().as_numeric()]
              corners2 = [page2.mediaBox.getLowerLeft_x().as_numeric(), page2.mediaBox.getLowerLeft_y().as_numeric(),
                          page2.mediaBox.getUpperLeft_x().as_numeric(), page2.mediaBox.getUpperLeft_y().as_numeric(),
                          page2.mediaBox.getUpperRight_x().as_numeric(), page2.mediaBox.getUpperRight_y().as_numeric(),
                          page2.mediaBox.getLowerRight_x().as_numeric(), page2.mediaBox.getLowerRight_y().as_numeric()]
              if ctm is not None:
                  ctm = [float(x) for x in ctm]
                  new_x = [ctm[0]*corners2[i] + ctm[2]*corners2[i+1] + ctm[4] for i in range(0, 8, 2)]
                  new_y = [ctm[1]*corners2[i] + ctm[3]*corners2[i+1] + ctm[5] for i in range(0, 8, 2)]
              else:
                  new_x = corners2[0:8:2]
                  new_y = corners2[1:8:2]
              lowerleft = [min(new_x), min(new_y)]
              upperright = [max(new_x), max(new_y)]
              lowerleft = [min(corners1[0], lowerleft[0]), min(corners1[1], lowerleft[1])]
              upperright = [max(corners1[2], upperright[0]), max(corners1[3], upperright[1])]
  
              self.mediaBox.setLowerLeft(lowerleft)
              self.mediaBox.setUpperRight(upperright)
  
          self[NameObject('/Contents')] = ContentStream(newContentArray, self.pdf)
          self[NameObject('/Resources')] = newResources
          self[NameObject('/Annots')] = newAnnots
  
      def mergeTransformedPage(self, page2, ctm, expand=False):
          """
          This is similar to mergePage, but a transformation matrix is
          applied to the merged stream.
  
          :param PageObject page2: The page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          :param tuple ctm: a 6-element tuple containing the operands of the
              transformation matrix
          :param bool expand: Whether the page should be expanded to fit the dimensions
              of the page to be merged.
          """
          self._mergePage(page2, lambda page2Content:
              PageObject._addTransformationMatrix(page2Content, page2.pdf, ctm), ctm, expand)
  
      def mergeScaledPage(self, page2, scale, expand=False):
          """
          This is similar to mergePage, but the stream to be merged is scaled
          by appling a transformation matrix.
  
          :param PageObject page2: The page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          :param float scale: The scaling factor
          :param bool expand: Whether the page should be expanded to fit the
              dimensions of the page to be merged.
          """
          # CTM to scale : [ sx 0 0 sy 0 0 ]
          return self.mergeTransformedPage(page2, [scale, 0,
                                                   0,      scale,
                                                   0,      0], expand)
  
      def mergeRotatedPage(self, page2, rotation, expand=False):
          """
          This is similar to mergePage, but the stream to be merged is rotated
          by appling a transformation matrix.
  
          :param PageObject page2: the page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          :param float rotation: The angle of the rotation, in degrees
          :param bool expand: Whether the page should be expanded to fit the
              dimensions of the page to be merged.
          """
          rotation = math.radians(rotation)
          return self.mergeTransformedPage(page2,
              [math.cos(rotation),  math.sin(rotation),
               -math.sin(rotation), math.cos(rotation),
               0,                   0], expand)
  
      def mergeTranslatedPage(self, page2, tx, ty, expand=False):
          """
          This is similar to mergePage, but the stream to be merged is translated
          by appling a transformation matrix.
  
          :param PageObject page2: the page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          :param float tx: The translation on X axis
          :param float ty: The translation on Y axis
          :param bool expand: Whether the page should be expanded to fit the
              dimensions of the page to be merged.
          """
          return self.mergeTransformedPage(page2, [1,  0,
                                                   0,  1,
                                                   tx, ty], expand)
  
      def mergeRotatedTranslatedPage(self, page2, rotation, tx, ty, expand=False):
          """
          This is similar to mergePage, but the stream to be merged is rotated
          and translated by appling a transformation matrix.
  
          :param PageObject page2: the page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          :param float tx: The translation on X axis
          :param float ty: The translation on Y axis
          :param float rotation: The angle of the rotation, in degrees
          :param bool expand: Whether the page should be expanded to fit the
              dimensions of the page to be merged.
          """
  
          translation = [[1, 0, 0],
                         [0, 1, 0],
                         [-tx, -ty, 1]]
          rotation = math.radians(rotation)
          rotating = [[math.cos(rotation), math.sin(rotation), 0],
                      [-math.sin(rotation), math.cos(rotation), 0],
                      [0,                  0,                  1]]
          rtranslation = [[1, 0, 0],
                         [0, 1, 0],
                         [tx, ty, 1]]
          ctm = utils.matrixMultiply(translation, rotating)
          ctm = utils.matrixMultiply(ctm, rtranslation)
  
          return self.mergeTransformedPage(page2, [ctm[0][0], ctm[0][1],
                                                   ctm[1][0], ctm[1][1],
                                                   ctm[2][0], ctm[2][1]], expand)
  
      def mergeRotatedScaledPage(self, page2, rotation, scale, expand=False):
          """
          This is similar to mergePage, but the stream to be merged is rotated
          and scaled by appling a transformation matrix.
  
          :param PageObject page2: the page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          :param float rotation: The angle of the rotation, in degrees
          :param float scale: The scaling factor
          :param bool expand: Whether the page should be expanded to fit the
              dimensions of the page to be merged.
          """
          rotation = math.radians(rotation)
          rotating = [[math.cos(rotation), math.sin(rotation), 0],
                      [-math.sin(rotation), math.cos(rotation), 0],
                      [0,                  0,                  1]]
          scaling = [[scale, 0,    0],
                     [0,    scale, 0],
                     [0,    0,    1]]
          ctm = utils.matrixMultiply(rotating, scaling)
  
          return self.mergeTransformedPage(page2,
                                           [ctm[0][0], ctm[0][1],
                                            ctm[1][0], ctm[1][1],
                                            ctm[2][0], ctm[2][1]], expand)
  
      def mergeScaledTranslatedPage(self, page2, scale, tx, ty, expand=False):
          """
          This is similar to mergePage, but the stream to be merged is translated
          and scaled by appling a transformation matrix.
  
          :param PageObject page2: the page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          :param float scale: The scaling factor
          :param float tx: The translation on X axis
          :param float ty: The translation on Y axis
          :param bool expand: Whether the page should be expanded to fit the
              dimensions of the page to be merged.
          """
  
          translation = [[1, 0, 0],
                         [0, 1, 0],
                         [tx, ty, 1]]
          scaling = [[scale, 0,    0],
                     [0,    scale, 0],
                     [0,    0,    1]]
          ctm = utils.matrixMultiply(scaling, translation)
  
          return self.mergeTransformedPage(page2, [ctm[0][0], ctm[0][1],
                                                   ctm[1][0], ctm[1][1],
                                                   ctm[2][0], ctm[2][1]], expand)
  
      def mergeRotatedScaledTranslatedPage(self, page2, rotation, scale, tx, ty, expand=False):
          """
          This is similar to mergePage, but the stream to be merged is translated,
          rotated and scaled by appling a transformation matrix.
  
          :param PageObject page2: the page to be merged into this one. Should be
              an instance of :class:`PageObject<PageObject>`.
          :param float tx: The translation on X axis
          :param float ty: The translation on Y axis
          :param float rotation: The angle of the rotation, in degrees
          :param float scale: The scaling factor
          :param bool expand: Whether the page should be expanded to fit the
              dimensions of the page to be merged.
          """
          translation = [[1, 0, 0],
                         [0, 1, 0],
                         [tx, ty, 1]]
          rotation = math.radians(rotation)
          rotating = [[math.cos(rotation), math.sin(rotation), 0],
                      [-math.sin(rotation), math.cos(rotation), 0],
                      [0,                  0,                  1]]
          scaling = [[scale, 0,    0],
                     [0,    scale, 0],
                     [0,    0,    1]]
          ctm = utils.matrixMultiply(rotating, scaling)
          ctm = utils.matrixMultiply(ctm, translation)
  
          return self.mergeTransformedPage(page2, [ctm[0][0], ctm[0][1],
                                                   ctm[1][0], ctm[1][1],
                                                   ctm[2][0], ctm[2][1]], expand)
  
      ##
      # Applys a transformation matrix the page.
      #
      # @param ctm   A 6 elements tuple containing the operands of the
      #              transformation matrix
      def addTransformation(self, ctm):
          """
          Applies a transformation matrix to the page.
  
          :param tuple ctm: A 6-element tuple containing the operands of the
              transformation matrix.
          """
          originalContent = self.getContents()
          if originalContent is not None:
              newContent = PageObject._addTransformationMatrix(
                  originalContent, self.pdf, ctm)
              newContent = PageObject._pushPopGS(newContent, self.pdf)
              self[NameObject('/Contents')] = newContent
  
      def scale(self, sx, sy):
          """
          Scales a page by the given factors by appling a transformation
          matrix to its content and updating the page size.
  
          :param float sx: The scaling factor on horizontal axis.
          :param float sy: The scaling factor on vertical axis.
          """
          self.addTransformation([sx, 0,
                                  0,  sy,
                                  0,  0])
          self.mediaBox = RectangleObject([
              float(self.mediaBox.getLowerLeft_x()) * sx,
              float(self.mediaBox.getLowerLeft_y()) * sy,
              float(self.mediaBox.getUpperRight_x()) * sx,
              float(self.mediaBox.getUpperRight_y()) * sy])
          if "/VP" in self:
              viewport = self["/VP"]
              if isinstance(viewport, ArrayObject):
                  bbox = viewport[0]["/BBox"]
              else:
                  bbox = viewport["/BBox"]
              scaled_bbox = RectangleObject([
                  float(bbox[0]) * sx,
                  float(bbox[1]) * sy,
                  float(bbox[2]) * sx,
                  float(bbox[3]) * sy])
              if isinstance(viewport, ArrayObject):
                  self[NameObject("/VP")][NumberObject(0)][NameObject("/BBox")] = scaled_bbox
              else:
                  self[NameObject("/VP")][NameObject("/BBox")] = scaled_bbox
  
      def scaleBy(self, factor):
          """
          Scales a page by the given factor by appling a transformation
          matrix to its content and updating the page size.
  
          :param float factor: The scaling factor (for both X and Y axis).
          """
          self.scale(factor, factor)
  
      def scaleTo(self, width, height):
          """
          Scales a page to the specified dimentions by appling a
          transformation matrix to its content and updating the page size.
  
          :param float width: The new width.
          :param float height: The new heigth.
          """
          sx = width / float(self.mediaBox.getUpperRight_x() -
                        self.mediaBox.getLowerLeft_x ())
          sy = height / float(self.mediaBox.getUpperRight_y() -
                         self.mediaBox.getLowerLeft_y ())
          self.scale(sx, sy)
  
      def compressContentStreams(self):
          """
          Compresses the size of this page by joining all content streams and
          applying a FlateDecode filter.
  
          However, it is possible that this function will perform no action if
          content stream compression becomes "automatic" for some reason.
          """
          content = self.getContents()
          if content is not None:
              if not isinstance(content, ContentStream):
                  content = ContentStream(content, self.pdf)
              self[NameObject("/Contents")] = content.flateEncode()
  
      def extractText(self):
          """
          Locate all text drawing commands, in the order they are provided in the
          content stream, and extract the text.  This works well for some PDF
          files, but poorly for others, depending on the generator used.  This will
          be refined in the future.  Do not rely on the order of text coming out of
          this function, as it will change if this function is made more
          sophisticated.
  
          :return: a unicode string object.
          """
          text = u_("")
          content = self["/Contents"].getObject()
          if not isinstance(content, ContentStream):
              content = ContentStream(content, self.pdf)
          # Note: we check all strings are TextStringObjects.  ByteStringObjects
          # are strings where the byte->string encoding was unknown, so adding
          # them to the text here would be gibberish.
          for operands, operator in content.operations:
              if operator == b_("Tj"):
                  _text = operands[0]
                  if isinstance(_text, TextStringObject):
                      text += _text
              elif operator == b_("T*"):
                  text += "\n"
              elif operator == b_("'"):
                  text += "\n"
                  _text = operands[0]
                  if isinstance(_text, TextStringObject):
                      text += operands[0]
              elif operator == b_('"'):
                  _text = operands[2]
                  if isinstance(_text, TextStringObject):
                      text += "\n"
                      text += _text
              elif operator == b_("TJ"):
                  for i in operands[0]:
                      if isinstance(i, TextStringObject):
                          text += i
                  text += "\n"
          return text
  
      mediaBox = createRectangleAccessor("/MediaBox", ())
      """
      A :class:`RectangleObject<PyPDF2.generic.RectangleObject>`, expressed in default user space units,
      defining the boundaries of the physical medium on which the page is
      intended to be displayed or printed.
      """
  
      cropBox = createRectangleAccessor("/CropBox", ("/MediaBox",))
      """
      A :class:`RectangleObject<PyPDF2.generic.RectangleObject>`, expressed in default user space units,
      defining the visible region of default user space.  When the page is
      displayed or printed, its contents are to be clipped (cropped) to this
      rectangle and then imposed on the output medium in some
      implementation-defined manner.  Default value: same as :attr:`mediaBox<mediaBox>`.
      """
  
      bleedBox = createRectangleAccessor("/BleedBox", ("/CropBox", "/MediaBox"))
      """
      A :class:`RectangleObject<PyPDF2.generic.RectangleObject>`, expressed in default user space units,
      defining the region to which the contents of the page should be clipped
      when output in a production enviroment.
      """
  
      trimBox = createRectangleAccessor("/TrimBox", ("/CropBox", "/MediaBox"))
      """
      A :class:`RectangleObject<PyPDF2.generic.RectangleObject>`, expressed in default user space units,
      defining the intended dimensions of the finished page after trimming.
      """
  
      artBox = createRectangleAccessor("/ArtBox", ("/CropBox", "/MediaBox"))
      """
      A :class:`RectangleObject<PyPDF2.generic.RectangleObject>`, expressed in default user space units,
      defining the extent of the page's meaningful content as intended by the
      page's creator.
      """
  
  
  class ContentStream(DecodedStreamObject):
      def __init__(self, stream, pdf):
          self.pdf = pdf
          self.operations = []
          # stream may be a StreamObject or an ArrayObject containing
          # multiple StreamObjects to be cat'd together.
          stream = stream.getObject()
          if isinstance(stream, ArrayObject):
              data = b_("")
              for s in stream:
                  data += s.getObject().getData()
              stream = BytesIO(b_(data))
          else:
              stream = BytesIO(b_(stream.getData()))
          self.__parseContentStream(stream)
  
      def __parseContentStream(self, stream):
          # file("f:\\tmp.txt", "w").write(stream.read())
          stream.seek(0, 0)
          operands = []
          while True:
              peek = readNonWhitespace(stream)
              if peek == b_('') or ord_(peek) == 0:
                  break
              stream.seek(-1, 1)
              if peek.isalpha() or peek == b_("'") or peek == b_('"'):
                  operator = utils.readUntilRegex(stream,
                          NameObject.delimiterPattern, True)
                  if operator == b_("BI"):
                      # begin inline image - a completely different parsing
                      # mechanism is required, of course... thanks buddy...
                      assert operands == []
                      ii = self._readInlineImage(stream)
                      self.operations.append((ii, b_("INLINE IMAGE")))
                  else:
                      self.operations.append((operands, operator))
                      operands = []
              elif peek == b_('%'):
                  # If we encounter a comment in the content stream, we have to
                  # handle it here.  Typically, readObject will handle
                  # encountering a comment -- but readObject assumes that
                  # following the comment must be the object we're trying to
                  # read.  In this case, it could be an operator instead.
                  while peek not in (b_('\r'), b_('\n')):
                      peek = stream.read(1)
              else:
                  operands.append(readObject(stream, None))
  
      def _readInlineImage(self, stream):
          # begin reading just after the "BI" - begin image
          # first read the dictionary of settings.
          settings = DictionaryObject()
          while True:
              tok = readNonWhitespace(stream)
              stream.seek(-1, 1)
              if tok == b_("I"):
                  # "ID" - begin of image data
                  break
              key = readObject(stream, self.pdf)
              tok = readNonWhitespace(stream)
              stream.seek(-1, 1)
              value = readObject(stream, self.pdf)
              settings[key] = value
          # left at beginning of ID
          tmp = stream.read(3)
          assert tmp[:2] == b_("ID")
          data = b_("")
          while True:
              # Read the inline image, while checking for EI (End Image) operator.
              tok = stream.read(1)
              if tok == b_("E"):
                  # Check for End Image
                  tok2 = stream.read(1)
                  if tok2 == b_("I"):
                      # Data can contain EI, so check for the Q operator.
                      tok3 = stream.read(1)
                      info = tok + tok2
                      # We need to find whitespace between EI and Q.
                      has_q_whitespace = False
                      while tok3 in utils.WHITESPACES:
                          has_q_whitespace = True
                          info += tok3
                          tok3 = stream.read(1)
                      if tok3 == b_("Q") and has_q_whitespace:
                          stream.seek(-1, 1)
                          break
                      else:
                          stream.seek(-1,1)
                          data += info
                  else:
                      stream.seek(-1, 1)
                      data += tok
              else:
                  data += tok
          return {"settings": settings, "data": data}
  
      def _getData(self):
          newdata = BytesIO()
          for operands, operator in self.operations:
              if operator == b_("INLINE IMAGE"):
                  newdata.write(b_("BI"))
                  dicttext = BytesIO()
                  operands["settings"].writeToStream(dicttext, None)
                  newdata.write(dicttext.getvalue()[2:-2])
                  newdata.write(b_("ID "))
                  newdata.write(operands["data"])
                  newdata.write(b_("EI"))
              else:
                  for op in operands:
                      op.writeToStream(newdata, None)
                      newdata.write(b_(" "))
                  newdata.write(b_(operator))
              newdata.write(b_("\n"))
          return newdata.getvalue()
  
      def _setData(self, value):
          self.__parseContentStream(BytesIO(b_(value)))
  
      _data = property(_getData, _setData)
  
  
  class DocumentInformation(DictionaryObject):
      """
      A class representing the basic document metadata provided in a PDF File.
      This class is accessible through
      :meth:`getDocumentInfo()<PyPDF2.PdfFileReader.getDocumentInfo()>`
  
      All text properties of the document metadata have
      *two* properties, eg. author and author_raw. The non-raw property will
      always return a ``TextStringObject``, making it ideal for a case where
      the metadata is being displayed. The raw property can sometimes return
      a ``ByteStringObject``, if PyPDF2 was unable to decode the string's
      text encoding; this requires additional safety in the caller and
      therefore is not as commonly accessed.
      """
  
      def __init__(self):
          DictionaryObject.__init__(self)
  
      def getText(self, key):
          retval = self.get(key, None)
          if isinstance(retval, TextStringObject):
              return retval
          return None
  
      title = property(lambda self: self.getText("/Title"))
      """Read-only property accessing the document's **title**.
      Returns a unicode string (``TextStringObject``) or ``None``
      if the title is not specified."""
      title_raw = property(lambda self: self.get("/Title"))
      """The "raw" version of title; can return a ``ByteStringObject``."""
  
      author = property(lambda self: self.getText("/Author"))
      """Read-only property accessing the document's **author**.
      Returns a unicode string (``TextStringObject``) or ``None``
      if the author is not specified."""
      author_raw = property(lambda self: self.get("/Author"))
      """The "raw" version of author; can return a ``ByteStringObject``."""
  
      subject = property(lambda self: self.getText("/Subject"))
      """Read-only property accessing the document's **subject**.
      Returns a unicode string (``TextStringObject``) or ``None``
      if the subject is not specified."""
      subject_raw = property(lambda self: self.get("/Subject"))
      """The "raw" version of subject; can return a ``ByteStringObject``."""
  
      creator = property(lambda self: self.getText("/Creator"))
      """Read-only property accessing the document's **creator**. If the
      document was converted to PDF from another format, this is the name of the
      application (e.g. OpenOffice) that created the original document from
      which it was converted. Returns a unicode string (``TextStringObject``)
      or ``None`` if the creator is not specified."""
      creator_raw = property(lambda self: self.get("/Creator"))
      """The "raw" version of creator; can return a ``ByteStringObject``."""
  
      producer = property(lambda self: self.getText("/Producer"))
      """Read-only property accessing the document's **producer**.
      If the document was converted to PDF from another format, this is
      the name of the application (for example, OSX Quartz) that converted
      it to PDF. Returns a unicode string (``TextStringObject``)
      or ``None`` if the producer is not specified."""
      producer_raw = property(lambda self: self.get("/Producer"))
      """The "raw" version of producer; can return a ``ByteStringObject``."""
  
  
  def convertToInt(d, size):
      if size > 8:
          raise utils.PdfReadError("invalid size in convertToInt")
      d = b_("\x00\x00\x00\x00\x00\x00\x00\x00") + b_(d)
      d = d[-8:]
      return struct.unpack(">q", d)[0]
  
  # ref: pdf1.8 spec section 3.5.2 algorithm 3.2
  _encryption_padding = b_('\x28\xbf\x4e\x5e\x4e\x75\x8a\x41\x64\x00\x4e\x56') + \
          b_('\xff\xfa\x01\x08\x2e\x2e\x00\xb6\xd0\x68\x3e\x80\x2f\x0c') + \
          b_('\xa9\xfe\x64\x53\x69\x7a')
  
  
  # Implementation of algorithm 3.2 of the PDF standard security handler,
  # section 3.5.2 of the PDF 1.6 reference.
  def _alg32(password, rev, keylen, owner_entry, p_entry, id1_entry, metadata_encrypt=True):
      # 1. Pad or truncate the password string to exactly 32 bytes.  If the
      # password string is more than 32 bytes long, use only its first 32 bytes;
      # if it is less than 32 bytes long, pad it by appending the required number
      # of additional bytes from the beginning of the padding string
      # (_encryption_padding).
      password = b_((str_(password) + str_(_encryption_padding))[:32])
      # 2. Initialize the MD5 hash function and pass the result of step 1 as
      # input to this function.
      import struct
      m = md5(password)
      # 3. Pass the value of the encryption dictionary's /O entry to the MD5 hash
      # function.
      m.update(owner_entry.original_bytes)
      # 4. Treat the value of the /P entry as an unsigned 4-byte integer and pass
      # these bytes to the MD5 hash function, low-order byte first.
      p_entry = struct.pack('<i', p_entry)
      m.update(p_entry)
      # 5. Pass the first element of the file's file identifier array to the MD5
      # hash function.
      m.update(id1_entry.original_bytes)
      # 6. (Revision 3 or greater) If document metadata is not being encrypted,
      # pass 4 bytes with the value 0xFFFFFFFF to the MD5 hash function.
      if rev >= 3 and not metadata_encrypt:
          m.update(b_("\xff\xff\xff\xff"))
      # 7. Finish the hash.
      md5_hash = m.digest()
      # 8. (Revision 3 or greater) Do the following 50 times: Take the output
      # from the previous MD5 hash and pass the first n bytes of the output as
      # input into a new MD5 hash, where n is the number of bytes of the
      # encryption key as defined by the value of the encryption dictionary's
      # /Length entry.
      if rev >= 3:
          for i in range(50):
              md5_hash = md5(md5_hash[:keylen]).digest()
      # 9. Set the encryption key to the first n bytes of the output from the
      # final MD5 hash, where n is always 5 for revision 2 but, for revision 3 or
      # greater, depends on the value of the encryption dictionary's /Length
      # entry.
      return md5_hash[:keylen]
  
  
  # Implementation of algorithm 3.3 of the PDF standard security handler,
  # section 3.5.2 of the PDF 1.6 reference.
  def _alg33(owner_pwd, user_pwd, rev, keylen):
      # steps 1 - 4
      key = _alg33_1(owner_pwd, rev, keylen)
      # 5. Pad or truncate the user password string as described in step 1 of
      # algorithm 3.2.
      user_pwd = b_((user_pwd + str_(_encryption_padding))[:32])
      # 6. Encrypt the result of step 5, using an RC4 encryption function with
      # the encryption key obtained in step 4.
      val = utils.RC4_encrypt(key, user_pwd)
      # 7. (Revision 3 or greater) Do the following 19 times: Take the output
      # from the previous invocation of the RC4 function and pass it as input to
      # a new invocation of the function; use an encryption key generated by
      # taking each byte of the encryption key obtained in step 4 and performing
      # an XOR operation between that byte and the single-byte value of the
      # iteration counter (from 1 to 19).
      if rev >= 3:
          for i in range(1, 20):
              new_key = ''
              for l in range(len(key)):
                  new_key += chr(ord_(key[l]) ^ i)
              val = utils.RC4_encrypt(new_key, val)
      # 8. Store the output from the final invocation of the RC4 as the value of
      # the /O entry in the encryption dictionary.
      return val
  
  
  # Steps 1-4 of algorithm 3.3
  def _alg33_1(password, rev, keylen):
      # 1. Pad or truncate the owner password string as described in step 1 of
      # algorithm 3.2.  If there is no owner password, use the user password
      # instead.
      password = b_((password + str_(_encryption_padding))[:32])
      # 2. Initialize the MD5 hash function and pass the result of step 1 as
      # input to this function.
      m = md5(password)
      # 3. (Revision 3 or greater) Do the following 50 times: Take the output
      # from the previous MD5 hash and pass it as input into a new MD5 hash.
      md5_hash = m.digest()
      if rev >= 3:
          for i in range(50):
              md5_hash = md5(md5_hash).digest()
      # 4. Create an RC4 encryption key using the first n bytes of the output
      # from the final MD5 hash, where n is always 5 for revision 2 but, for
      # revision 3 or greater, depends on the value of the encryption
      # dictionary's /Length entry.
      key = md5_hash[:keylen]
      return key
  
  
  # Implementation of algorithm 3.4 of the PDF standard security handler,
  # section 3.5.2 of the PDF 1.6 reference.
  def _alg34(password, owner_entry, p_entry, id1_entry):
      # 1. Create an encryption key based on the user password string, as
      # described in algorithm 3.2.
      key = _alg32(password, 2, 5, owner_entry, p_entry, id1_entry)
      # 2. Encrypt the 32-byte padding string shown in step 1 of algorithm 3.2,
      # using an RC4 encryption function with the encryption key from the
      # preceding step.
      U = utils.RC4_encrypt(key, _encryption_padding)
      # 3. Store the result of step 2 as the value of the /U entry in the
      # encryption dictionary.
      return U, key
  
  
  # Implementation of algorithm 3.4 of the PDF standard security handler,
  # section 3.5.2 of the PDF 1.6 reference.
  def _alg35(password, rev, keylen, owner_entry, p_entry, id1_entry, metadata_encrypt):
      # 1. Create an encryption key based on the user password string, as
      # described in Algorithm 3.2.
      key = _alg32(password, rev, keylen, owner_entry, p_entry, id1_entry)
      # 2. Initialize the MD5 hash function and pass the 32-byte padding string
      # shown in step 1 of Algorithm 3.2 as input to this function.
      m = md5()
      m.update(_encryption_padding)
      # 3. Pass the first element of the file's file identifier array (the value
      # of the ID entry in the document's trailer dictionary; see Table 3.13 on
      # page 73) to the hash function and finish the hash.  (See implementation
      # note 25 in Appendix H.)
      m.update(id1_entry.original_bytes)
      md5_hash = m.digest()
      # 4. Encrypt the 16-byte result of the hash, using an RC4 encryption
      # function with the encryption key from step 1.
      val = utils.RC4_encrypt(key, md5_hash)
      # 5. Do the following 19 times: Take the output from the previous
      # invocation of the RC4 function and pass it as input to a new invocation
      # of the function; use an encryption key generated by taking each byte of
      # the original encryption key (obtained in step 2) and performing an XOR
      # operation between that byte and the single-byte value of the iteration
      # counter (from 1 to 19).
      for i in range(1, 20):
          new_key = b_('')
          for l in range(len(key)):
              new_key += b_(chr(ord_(key[l]) ^ i))
          val = utils.RC4_encrypt(new_key, val)
      # 6. Append 16 bytes of arbitrary padding to the output from the final
      # invocation of the RC4 function and store the 32-byte result as the value
      # of the U entry in the encryption dictionary.
      # (implementator note: I don't know what "arbitrary padding" is supposed to
      # mean, so I have used null bytes.  This seems to match a few other
      # people's implementations)
      return val + (b_('\x00') * 16), key
  